ALMS will never race at Indy. The track has slowly become a 1 lane track since the aprons were removed. That was shown by Hildebrandt's crash on the final lap, among other incidents. It's worse for the NASCAR boys because the cars are bigger and less able to pass in the draft. The excitement of seeing stock cars on the famous track has worn off and now fans want to see racing. They don't get the 100 passes for the lead they are used to. Not sure adding a support race of either type will help. That said, I quite like Grand-Am. The cars are evenly matched, the drivers race very hard, and aero has very little to do with the outcome. You can see the cars sliding around and the drivers have to actually manage the throttle. And yes, they are low tech, but the racing is good and not every series is F1.
Lonny