This much is beyond dispute: the 2020 championship, even in its slimline form prompted by a global pandemic, will be a much poorer place for the absence of Jack McCaffrey.
But what does it mean for Dublin's defence of their seemingly perennial possession, Sam Maguire?
There are two ways of looking at this. You can cite 2016 as proof they have the squad to sustain the loss of a reigning Footballer of the Year. They still won it that year, without Jack.
Moreover, even when injuries brought a premature end to McCaffrey's All-Ireland day - against Mayo in 2017 and Kerry in last year's replay - his colleagues still found a way.
But no amount of positive spin can lessen the sense that a new chink of vulnerability has appeared in the armoury of a hitherto invincible force.
Over the past two years especially, McCaffrey has evolved into the complete half-back. His terrifying pace and dynamism and counter-attacking ambition were already the stuff of legend; but the quality of his defending, in the air and in the trenches, was just as evident in his Man of the Match performances, against Tyrone and Kerry, in back-to-back All-Irelands.
And it just so happens that Dublin, for all their embarrassment of riches, aren't weighed down with alternatives in a defence no longer immune to the passage of Father Time.
McCaffrey turns 27 in Octo ber; if so inclined, he has many more seasons left in his turbo-boosted legs. Who can possibly fill that void in November and December?
For Dessie Farrell, the news that his former minor protégé is taking a break, permanent or otherwise, from county football is a crushing blow. You can't dress it up any other way. It's not just the actual loss of a hard-to-replace marquee player.
It's the nagging sense of uncertainty it may engender in a squad that has lost its all-conquering manager in the off-season and then lost vital momentum when the lockdown came.
Farrell's bedding-in period has been cruelly compromised because of the pandemic.
You could argue he has now lost McCaffrey for the same reason. The player had made his seasonal return on that storm-lashed night in Omagh at the end of February, only for injury to shorten his cameo off the bench.
Surely it's reasonable to speculate that, in a world without Covid, one where the Leinster final should have been played nine days ago, the Clontarf man would have stayed involved? Back in January he had described the prospect of "getting started under Dessie" as "really exciting".
True, he was about to start a six-month stint in St Luke's Hospital, Kilkenny, one liable to curtail his early-season involvement. But he had also met with Farrell, and the two had targeted "specific dates it would be important to be available for."
However, the cessation of all sport has opened a window for reflection and, for whatever reason or reasons, McCaffrey has decided to walk away from the inter-county game. For now; perhaps even forever.
It's worth noting that the Sunday Independent has reported its understanding that his decision is not linked to the coronavirus crisis and his frontline role as a medical doctor.
The trouble for Dublin is that McCaffrey is a once-in-a-generation talent. Managers usually don't require specific man-marking strategies for an opposing wing-back - with Jack it was a necessity, even if you ran the risk of disrupting your own attacking game-plan in the process.
Losing the player now is all the more potentially damaging because of Dublin's age profile in defence and the relative dearth of options there.
There are just three defenders of a similar vintage who qualify as proven at this level. Eoin Murchan, 24 in August, is another possessing rapier pace; one who scored a goal that carried all the hallmarks of Jack on the loose in last September's All-Ireland replay.
David Byrne, 26, enjoyed his best Dublin season in 2019 and carried that form into the league.
John Small, for all his propensity for cards, has been a flinty mainstay of the half-back line under Jim Gavin and is set to remain so under Farrell.
But the rest of Dublin's established defenders - even those still performing at or close to their All Star peak - are the wrong side of 30.
Leaving aside the incredible outlier than is Stephen Cluxton (39 in December), there are six outfield defenders in that bracket. By the time this year's revised championship concludes six days before Christmas, Philly McMahon will be 33, Cian O'Sullivan and Mick Fitzsimons 32, Johnny Cooper and Rory O'Carroll 31, and James McCarthy 30.
It's true that neither Fitzsimons nor McCarthy has shown any noticeable signs of slippage to date - but McCarthy has increasingly been needed at midfield in recent summers.
Both McMahon and the injury-blighted O'Sullivan had lost their ever-present status by the time Dublin completed the five-in-a-row, while Cooper also endured a difficult, injury-disrupted 2019, most evident in his drawn final red card woes in the slipstream of David Clifford.
None of this should be misconstrued as evidence that Dublin are there for the taking when - fingers crossed and virus still suppressed - inter-county football returns.
Even without a back door safety net (one they haven't required since 2010) the provincial road looks risk-free. On that basis, they just need to peak for two matches - a semi-final against the best of Ulster, and then a December 19 finale.
And if that were against Kerry? Let's just say that Peter Keane would be a much happier manager not to have 'stopping Jack' in his in-tray.
As Kieran Donaghy tweeted yesterday, when Kerry were the aggressors last year and pressed up on kickouts, "this fella broke our hearts with a scintillating goal, so much so we were afraid to press in the replay."
In the aftermath of that historic All-Ireland, McCaffrey spoke of visiting the hospitals in Crumlin and Temple Street as "one of the greatest honours I've ever had in my life. You walk in and see kids who are sick and families who are on a tough journey. And to see the joy that us playing football gives them is astounding.
"Some people say it puts things in perspective; football doesn't really matter.
"No, it absolutely highlights how much sport matters and how special what we've managed to do is."
It won't be quite as special without him.