Because they already have something that works. Why switch if theres no advantage.

Because people want to protect their businesses?

I don't even think it makes sense to use the closed, API-access models for core business functions. Seems like an existential risk to be handing over that kind of information to a third party in the age of AI.

But handing it over to the guy who is simultaneously running for-profit companies that contract with the government and seizing control of the Treasury? To a guy who has a long history of SEC issues, and who was caught cheating at a video game just to convince everyone he's a genius? That just seems incredibly short-sighted.