Vince is delusional. The XFL didn't fail because the trucks went out or because it was crass. The XFL failed for the same reason every other competitor to a deeply-entrenched sports league has always failed: in the long run, no one wants to watch a substandard game played by substandard players. So while the Trump crotchsniffers are all excited that they can start their own football league with blackjack and hookers, they may want to look up the history of the USFL and see what happened the last time their "god emperor" tried to take on the NFL.
In some cases you can compete well enough to force a partial or complete merger. The NBA absorbed four ABA teams (Nuggets, Spurs, Pacers, Nets), the NHL absorbed four WHA teams (Nordiques, Jets, Whalers, Oilers), and the NFL absorbed the entire AFL (Broncos, Bills, Patriots, Jets, Dolphins, Bengals, Chiefs, Chargers, Raiders, Oilers). Granted this was the 1960s and 1970s but it has happened.
But that ain't happening this time.