I feel like most folks don't know the financials of both leagues. They are both supported by TV networks. XFL by ESPN, USFL by Fox and NBC. Attendance is what it is, but TV ratings were good enough to keep going. Don't forget gambling revenue too.
Like I said before, over 100 players were brought into NFL camps this year. Even the Bills have (I think) 2 on the PS now. It's doing what it's supposed to do.