Two thoughts:
1) People would bitch about too many repeat bands, getting sick of seeing the same band every other year, and it would end up hurting draw. People will always find something to bitch about, but the novelty of seeing new bands is an important draw to get some people to travel.
2) There's not a dwindling number of good bands in the genre, far from it I'd say - there's just a dwindling number of headliners that are going to make people's jaws drop. If anything, I'd say he has more options than ever for the lower slots - there are a ton of younger bands putting out awesome material. It's at the top of the card where he runs into the issues of bands being too expensive, touring too often (and therefore hurting their ability to get people to travel for them), or any other number of reasons.
If Glenn decided to keep the fest going another 5 to 10 years - and this is hypothetical, he has been very honest about the health and longevity of PPUSA - it's entirely possible that he could have a new class of headlining bands on his hands. But then he'd likely run into the same problems of them touring, growing too big, etc. It's sad to say, but the best scenario for Glenn would be for touring in America to continue going down the shitter, allowing him to have more exclusivity with high tier bands.
All I can think of right now is...two more nights at home then I'm the A.T.L.!!!!!
