They were in the ALMS for a reason, and that was not for the Daytona 24....
And from what I understand there is still no word on the «US Race» in the WEC. As it stands it looks like next year might be the last year Sebring will host a round of the WEC for some time.
The ACO wants Lemans as the centerpiece race for both sponsors and teams. Having the GT's as the only link to Lemans is short, and I doubt the ACO will buy it. The ACO wants the big names in the big LMP1 class and probably could care less if the Corvettes don't show up. The centerpiece of Grand Am is the Daytona 24 and I suspect it will remain the Daytona 24.
BMW, Ferrari, Porsche are all european brands that are likely to adopt ACO regulations first if that means entering Lemans, and when I mean regulations I mean not just car specs, I also mean garanteed starting entry rules. That does not mean there will be parity in the car regulations. But the ACO might introduce some annoying requirements that would outlaw the american GT rules or make such entries more difficult. Unfortunately that could mean bad news for the american teams. The few words I got from Don Panoz seems to indicate that many teams still want to race in Lemans and that is probably what's in the talks right now.
Which goes back to my initial post. These 2 sanctioning bodies (NASCAR and ACO) could have taken the opportunity to align some rules that would allow them to bolster the grids in their races instead of going diferent paths risking their grids to become smaller. Teams race for the passion of it, they would race in Daytona, Lemans, Sebring, Fuj and even the Moon if budget allowed.
If I was running that show I would talk to the ACO about merging the LMP2 and DP2 class rules into a global spec that is legal in Daytona and Lemans. Fine, leave the 1 classes for the big boys, but we should keep in mind that nearly 20 years later there is still no heir to the group c class and prototype classes are considered THE sport car racers.