When will comic book film bubble burst?
It's been a lean time for superhero fans, who've had to wait a whole three months for some fresh cinematic action.
But the famine is over, and next week a brand new Marvel/Disney hero will engulf the nation's multiplexes. Doctor Strange, an action fantasy based on a character created by Steve Ditko 53 years ago, stars Benedict Cumberbatch (pictured below) as Stephen Strange, a brilliant but rather arrogant neurosurgeon who's forced to reassess his life after his hands are badly injured in a car crash.
When he sets out on a journey of healing, Doctor Strange encounters the Ancient One (Tilda Swinton), a Celtic mystic who opens his eyes to a whole new world of spirituality and magic. Strange becomes a fearsome warrior, a master of martial arts and spells who uses portals to travel through space and time at will.
It says a lot about the omnipresence of superhero films that this one ever got made. Hero fans loiter online in the long grass waiting to pounce on unbelievers, and I'll probably be killed for saying this, but Doctor Strange is one of Marvel's obscurer creations. He was once voted 83rd on a list of the 200 greatest comic book characters, and I'll be honest - I had never heard of him until recently. But none of that matters, because superheroes have been Hollywood's hottest currency over the last decade, and any half-decent film belonging to the genre is pretty much guaranteed to make money.
A steady trickle of superhero movies that began in earnest in the early 2000s has thickened to a positive blizzard. This is the 14th film produced thus far by the Marvel Cinematic Universe, a stable of blockbusters clustered around the mighty Avengers brand, which does not include other ongoing Marvel vehicles, like X-Men, Spider-Man, Guardians of the Galaxy or the various TV spin-offs.
Marvel's big rival in the field is DC Comics, home of Batman, Superman, Wonder Woman, The Justice League and Suicide Squad. The DC characters are mainly the province of Warner Brothers, who've launched their own 'DC Extended Universe' that includes the recent Batman v Superman and will result in at least another eight big-budget hero films over the next three years. Marvel's plans are similarly open-ended, and the billions being made by these movies seem to amply justify their existence.
But their domination comes with a heavy cost. When the first real superhero movie (Richard Donner's Superman) appeared back in 1978, it emerged in a very different Hollywood. Though well made, it looked like a novelty act compared to the bold and challenging films being knocked out by the young guns of 'New Hollywood' - Coppola, De Palma, Scorsese, Spielberg - and seemed to pose no existential threat to originality.
But films were cheaper to make then, and somewhere around the late 1990s the big producers and studios lost their nerve entirely, and became chronically averse to taking risks on new scripts and ideas. As production costs spun ever higher, Hollywood producers looked for sure things; in other words stories and characters the public already knew. And what better source of second-hand ideas than the great American comic books?
After several false starts, the superhero trend took off in earnest in the 2000s, when the development of overarching franchises featuring vast stables of characters was encouraged in part by the self-fulfilling prophesy that only teenage boys went to the cinema. And the vast amounts of money involved in making them (the average Avengers movie costs $200m) ate up resources that might have made a dozen smaller, more interesting films.
Still, you can't argue with commerce: Avengers Assemble, which cost $220m to make, grossed over $1.5bn in 2012, and even this year's much derided Batman v Superman: Dawn of Justice grossed almost $900m.
The superhero craze shows no sign of abating, and over the next three years or so, dozens of sequels and spin-offs look sure to dominate the global box office. But superhero films are only the most visible aspect of Hollywood's increasing conservatism, and, in fairness, Warners and Marvel/Disney have made pretty good ones.
Richard Donner's Superman established the genre's template: a muscle-bound hero with special powers and a secret identity, a histrionic villain, a damsel in distress (optional) and ground-breaking special effects. A wry sense of humour was added to this very slick formula, but at first other film-makers struggled to replicate it.
A 1980 Superman sequel did ok, but thereafter the brand was debased by inferior follow-ups. The rare superhero films that appeared during the 1980s struggled to find any purchase with adult audiences, and the huge comic book fan base that now flocks to every Marvel release had yet to emerge. The genre would need to develop darker undercurrents if it was to appeal to a wider audience, and in 1989 Tim Burton's Batman obliged.
Burton's film was inspired by the Dark Knight comics of the mid-1980s, which depicted Batman as a grizzled vigilante whose ruthless methods were not always to be admired. His decision to cast the rather un-heroic looking Michael Keaton in the lead was controversial, but worked: his Batman was an uncertain character, plagued by demons and self-doubts, in a film dominated by Jack Nicholson's hammy and very amusing Joker.
Tim Burton's Batman was a huge hit, and proved that comic book stories had untapped dramatic possibilities. But again its success proved hard to capitalise on. A 1991 film of Captain America didn't get a US cinema release and was mercilessly panned elsewhere, and the derision heaped upon Joel Schumacher's dire 1997 sequel Batman & Robin seemed to suggest that the public's appetite for superhero yarns was finite. Not so, as it turns out.
In the year 2000, Fox had a surprise hit with X-Men, Bryan Singer's accomplished adaptation of the Marvel comic which used the latest CGI effects to make the mutants seem remarkably real. In fact it could be argued that primitive special effects had been the only thing preventing the superhero craze from taking off: now, all sorts of stunts, special powers and miraculous transformations could be convincingly rendered on-screen.
Sam Raimi's 2002 film Spider-Man was particularly praised for its effects, launching a very profitable franchise and inspiring numerous others. In 2005 Christopher Nolan revived the Batman brand by going back to basics and exploring the original story's dark psychological undercurrents.
And after a slow start to the decade in films like Daredevil and Punisher, Marvel really hit their stride in 2008 with Iron Man, a witty and spectacular action movie starring the perfectly cast Robert Downey as the cocksure inventor Tony Stark. Since then, the genre has really taken off, and superhero movies have come at us thick and fast.
Some, as I mentioned, have been nothing less than brilliant (see panel), but in recent years the bewildering proliferation of Marvel titles has led to a drearily formulaic approach, in which pre-packaged heroes joke and swagger their way towards the inevitable half-hour CGI climactic battle.
There have recently been attempts to broaden out the genre into satire: earlier this year, Marvel had a surprise hit with Deadpool, a black comedy that mined the genre for laughs. But while fans raved about it, Deadpool was loud, obnoxious, lazy and misogynistic.
Suicide Squad was slightly better, but not much, and for all its supposed subversive undercurrents looked pretty formulaic by the end. But it grossed $750m, and several sequels are already in the works. And so the superhero craze marches on, and some concerned movie-goers may be wondering when, if ever, it will stop.
In an interview with Esquire last year, Steven Spielberg tellingly compared superhero movies with the western, the once mighty genre that dominated Hollywood in the 1930s, 40s, and 50s but is now virtually non-existent.
"We were around when the western died," he said, "and there will be a time when the superhero movie goes the way of the western." All it would take, Spielberg concluded, was for "three or four or maybe even a half-dozen mega-budget movies" to go "crashing into the ground, and that's going to change the paradigm".
As the man who invented the modern blockbuster, Spielberg ought to know what he's talking about.
Let's hope so.
A superhero masterpiece
Apart from elaborate CGI tableaux, the superhero genre has added little to the language of cinema, and few of the hero movies will stand the test of time. But Christopher Nolan has proved that, with a little imagination, even a superhero movie can be turned into something substantial.
Nolan inherited Batman in the early 2000s, and moved the franchise into much darker and more adult territory with Batman Begins (2005), a film investigating Bruce Wayne's damaged psyche and his evolution into a crime-fighting vigilante.
But Batman Begins pales in comparison with its magnificently bleak successor, The Dark Knight (2008), a splendidly realised epic drama in which Batman does battle with his most famous adversary. Nolan shot on location in Chicago to make Gotham seem frighteningly real, and his direction told the story with commendable sweep, and flow.
Heath Ledger's shambling, demented Joker dominated the film, but there were lots of other fine performances, from Christian Bale's tortured Batman to Aaron Eckhart's conflicted DA Harvey Dent and Michael Caine's exasperated factotum Alfred. The Dark Knight is a thing of beauty from start to finish, and the greatest superhero of them all.