If any team goes bankrupt, it's not due to the salary floor. It's due to all the money mismanagement that took place well beforehand. Theoretically.
I think you're really reaching here.
Look plenty of teams go bankrupt because they can't manage money properly and I'm perfectly okay with that. But in this case the team that promotes ends up making LESS money than if it didn't promote, because of salary floor, despite featuring a roster perfectly adequate for avoiding relegation in their first season. Talk about an incentive to promote... Now I agree that going bankrupt would require many particular circumstances that are very unrealistic in most cases, yes.
Honestly, it looks like fixes being implemented over previous fixes to fix problems created by fixes themselves, and where is it going to end? Trim this fix-puzzle down. All this tanking is because the fan logic is flawed.
"Air is beautiful, yet you cannot see it. It's soft, yet you cannot touch it. Air is a little like my brain." - Jean-Claude Van Damme