I think growing up is a massive part of this.
I have much more going on in my life than Wrestling although i still like to keep up-to-date with it. In recent months i stopped watching ECW.... Then i only watched SD if i read something i liked in the spoilers..... And now i skim RAW most weeks due to time contraints.
I tried hard to keep up with TNA too but lost interest. I just don't have 8 hours a week to watch wrestling after work, so i read some weeks without watching a single minute of wrestling programming. If i was a student or unemployed i'd watch it all.. even TNA.
I have a loyalty to wrestling in terms of knowing whats going on, but the only thing i'll take time out to watch for certain is the PPV's.