Is there enough "top talent" to fund a new league? Take American football: there are more players in high school, than college, because the game gets faster and better; the same goes from college to the NFL. The game changes, too; so. success in college doe not mean success in the NFL. There have been 88 Heisman Trophy winners; but, only 10 have made the NFL Hall of Fame. (The only two-time Heisman Trpohy winner is not one of those ten.)
Did (DO) the XFL and AAF have "top talent"? These were players who were not good to get drafted by the NFL. Sure, some players have from the XFL to NFL; but, that makes the XFL more like a minor league or developmental league -- a notch lower.