The actual separation of powers that's a good idea is that between governments and companies.

Separation of powers is easy to erode and we are seeing that happening in a lot of western countries. Companies are, of course, never going to be trustworthy, but they at least can go out of business if they go full dystopian.

So how many user accounts should Apple or Google wrongfully close until they go out of business? 1000? 10,000? ...