If Usain Bolt decides tomorrow he is now a female, he can clean house both financially and competitively in the “women’s” events

No, no he can’t lol that’s not how it works. First of all you can’t decide you’re female, that’s biological sex again. He can come out as a trans women.

But to use the olympics as an example, the IOC's rules are that athletes must have undergone sex reassignment surgery, including changes in the external genitalia and gonadectomy. Second, athletes must show legal recognition of their gender. Third, athletes must have undergone hormone therapy for an appropriate time before participation, with two years being the suggested time.

This was later modified to require that trans woman athletes declare their gender and not change that assertion for four years, as well as demonstrate a testosterone level of less than 10 nanomoles per liter for at least one year prior to competition and throughout the period of eligibility.

So no, not usain bolt, nor any athlete really, would go through this whole process just to make a few bucks or dominate any sport. Wanna know how I know? These IOC rules have been in place since 2004. Not one trans Olympian. Not one person faking being trans either.