Interesting article. I won't dispute Trump's influence in ultimately dooming the USFL. However, it should also be remembered that the league was already in trouble when he came along, as teams were paying far more for players than they could afford.
Trump advocated a gamble that failed, but the league was doomed because folks just were not interested enough in spring football to make it an economically sustainable model. Instead of trying to be a league that could be a gap between college and NFL, they went head-to-head in competing for players like the AFL did in the 1960's. But, but the 1980's the NFL was much larger, more powerful, and had a lot deeper pockets than they did in the '60's.