Culturally, the players have gone in one direction since middle school when their talent was discovered. Likewise, the fan-base has gone off culturally in another direction, again starting in middle school when we make our first steps to prepare ourselves for college, skilled trades, military, police, etc.
Add on top of that, the cultural isolation of the "1%" who actually can afford to start up teams. Along with them goes their flunkies, the Ivy League MBAs that run the advertiser and broadcast media companies.
So in a nutshell, the problems with the NFL reflect the current mess of things in America.
- crowdsource a football league,
- televise it over the internet,
- sponsor it by local Mom & Pop businesses, and
- establish firm limits on how players comport themselves on and off the field?
But to try to simply recreate the USFL, as it was, would not do anything to change the fundamentals.