Bernie Madoff ran his Ponzi scheme for 25+ years... Just sayin.
Again, no way to prove 100%. But think about it, the Bitfinex CEO is already super rich from just operating one of the largest exchange.
Probably, he has a billion or more in legit money+ cryptos already. Why risk lifetime jail and bounty on your head just to make another billion or two
from printing tether?
Even super rich billionaire will always find ways how to be more richer and its not about because of the money instead its because of the "Fame". As viper had said "History is filled with rich people doing illegal things to get more richer".