I liked the USFL too. I thought it was good, fun football. And they attracted a surprisingly high number of NFL veterans and good college players. I always thought their collapse was mostly based on (1) expanding from 12 to 18 teams as a way to improve revenue (spread them too thin instead) and (b) hate to say it but Trump's involvement and ego in trying to take on the NFL, say they were moving to the fall, etc. That is a conversation to have if/when you've been successful for 7, 8, 9 years and have really established yourself. Not going into year 2.
If they could have been satisfied financially to have 12 teams attracting 25k-ish fans per game with the ABC TV contract they had they could have bumped along and established themselves.