I think the NFL is in fact losing appeal to many people who before were die hard. But I think it's for many different reasons. I know for me the sport has become even more violent than ever before. The players (even beginning in high school) are much bigger, faster, stronger, and the collisions and impacts are producing record number of injuries to players who are being lost for the season and maybe for their careers. Some people enjoy the violence-many don't. One person I know who played at USC (never in the pros) said "in a sane world the game would be illegal".
Anyway I don't watch anywhere near the football I used to. I watch the Rams play and that's it. I just don't care for the violence. But I know people who love it.