Baseball has never returned to the popularity before the strike. It's been 20 years and people are still pissed off about it. If what you're saying is true about people becoming disillusioned with stick and ball sports, then why is the NFL more popular than ever?
I can only tell you why Nascar lost me. I was a fan from as long as I could remember, so probably mid 80s all the way though the mid 2000s. I attended races at NW, Rockingham, and Charlotte, nascar left 2 of those tracks to rot. Then they changed the points system and the cars. They've over dramatized every single pass on the track.
It's too much for me, I can't watch it. I know for a fact I'm not the only one. One of my buddies that went to all those races with me for 10 years has stopped watching for the same exact reasons. I've heard numerous others same the same thing.
The unnecessary changes have to stop, proof is in the pudding. Attendance and TV ratings are ALL down.