Why are the laws of chess still being overseen by the same political-governing body called FIDE and not by an independent autonomous body like in other major sporting codes such as football where IFAB (International Football Association Board - which is an independent body that determines the Laws of the Game of association football outside FIFA)?
I'm going to answer with a question. In any case this was an opinion-based question so it's not like I can give a factual answer, and this is too long to post as a comment.
You make it sound as if IFAB took control of the Laws of the Game from FIFA, at least if we go by analogy with the idea of some organization taking control of the Laws of Chess from FIDE. But it turns out that IFAB is actually older than FIFA (1886 vs 1904). Maybe the case of football is just historical accident. I don't know about other sports.
My question to you is: why? What problem do you think would be solved by having the Laws of Chess be controlled by some other organization? Maybe you have a solution in search of a problem. Maybe chess by being a "smaller" sport doesn't need another layer of bureaucracy?