There's an irony that Audi should announce its withdrawal from the World Endurance Championship little more than a week after the closest finish in the history of the reborn series at Fuji, a race in which the three LMP1 manufacturers were separated by a shade under 16 seconds after six hours of racing.
The WEC can hang its hat, right now, on the fact that each of its factory participants at the sharp end of the field are in the hunt.
That's why the withdrawal of one of those manufacturers - and the one currently enjoying the longest run in the prototype ranks - is a major blow.
But is it a body blow? That depends on how you look at it.
Think back to those Audi versus Peugeot battles at the Le Mans 24 Hours and elsewhere that raged in the final years of the noughties before the arrival of another factory programme, admittedly a low-budget one, from Aston Martin.
Did we lament after the 2008 thriller at Le Mans that there was no third manufacturer at the party? If anyone did, I don't remember.
The WEC can survive on two manufacturers in LMP1. It was reborn with two in 2012, remember, though it should have been two and a half.
Peugeot ended its second prototype adventure ahead of the start of the inaugural season of the new-look WEC, and Toyota had to step up to the plate. It went from planning a come-and-go development year to a full programme, though admittedly one that never included the first race and turned out not to include the second either.
The problem is that championships - or classes within them - with only two participants are in their nature unstable. They are left exposed to the whims of the manufacturers.
There are many questions to be answered about the respective campaigns of the two manufacturers that will return to the WEC next year.
Toyota says there is no end-date to its LMP1 participation, but how long will it be willing to compete in the WEC alongside its renewed participation in the World Rally Championship?
And Porsche is not the company of old that raced for overall honours at Le Mans come what may, even hauling cars out of the museum for that purpose.
Come the end of its current campaign - confirmed until the end of 2018 - will it feel the need to keep going with a growing collection of silverware on its shelves? We don't know.
There is a caveat to this. What we don't know are the terms of WEC promoter the Automobile Club de l'Ouest's contract with FIA.
The original deal specified a minimum of two manufacturers in P1, hence the scurrying around to get Toyota to commit to more races. Plan b involved a spot of hoop-jumping and called on Honda, then sort of represented in the series by a pair of P1 customer chassis made by its Honda Performance Development offshoot, to become the second manufacturer.
There is the suggestion that the latest deal, signed in 2014 and covering the 2015-17 seasons, mandates three manufacturers in P1.
If the ACO did put pen to paper on such a deal, it must have been rock sure of the commitment of its existing manufacturers or wildly optimistic about the likelihood of another marque signing up.
Whatever, the P1 class is definitely vulnerable because I don't see any new factory P1 entrants on the horizon. But the ACO has a more pressing problem - the race it organises in France in the middle of June.
Two manufacturers in P1 means four cars. Add in the one privateer we're expecting back in the WEC next year following Rebellion Racing's withdrawal, and that makes five. Not ideal, but still knocking on 20% of the kind of grid numbers envisaged for the series next year.
But Le Mans is a different story. Even if Toyota opts to run three cars, LMP1 will amount to just 10% of the grid. That's not enough in a race where the rate of attrition is likely to be greater than a regular six-hour WEC race.
The privateer P1 ranks have dwindled in the face of the runaway development of the hybrid factory cars. Even a series of rules breaks for the non-hybrid independents for next season - and more scheduled for 2018 - haven't motivated any new entrants as yet.
A few weeks ago, someone suggested to me that one of the new breed of faster P2 cars could finish on the podium at Le Mans next year. I told them to get out of town.
The bombshell from Audi means I might have to reconsider my response.