You're the one who said:

socialism fundamentally requires centralized control, and I don't trust centralized control.

What did you mean when you said that? There is no way in which socialism "requires" anything like this that capitalism also doesn't require in terms of controlling the population. At least in socialism the population has control over the population rather than a small elite class (the bourgeoisie aka capitalist class aka owning class) as in capitalism. If you are talking about a planned economy, then again, capitalism does this too and you need look no further than fucking amazon as an example. The economy is just planned around gaining more capital for a small class instead of actually serving the needs of people as in socialism.

Finally,

I don't trust society not to deliberately appoint a tyrannical megalomaniac: I've seen them do it entirely too often.

No, you haven't. You've been told that happened as a means of propaganda to make sure you and everyone like you (people not part of the owning class) think exactly what you do now think "ooooooh noes scary socialism always turns ebil dictatortotship!" Show us what socialist societies (AES) "appointed a tyrannical megalomaniac" and we'll show you a load a bullshit that has been force-fed to the people of a capitalist society ruled by the real tyrannical megalomaniacs: the capitalist class.

What I mean by this is that there is no choice for capitalists but participate in our economic system. If a "nice" business owner tries to be fair to their workers, give them the full value of their labor, etc., then they will be out-competed by a company that does not. As long as workers continue working for a company (no strike or anything), then the safest course for a business to take is maximum profit and wage exploitation. This way, they keep wages down, their shareholders are happy, etc. Now, there's always a balancing act they put on so that workers don't realize this, be that platitudes like game rooms at tech start-ups, all the way to traditional methods like raising wages.

Because of this, businesses will naturally gravitate toward anti-worker practice. As late-stage capitalism progresses, this becomes even more brutal. Now the biggest companies maintain their competitive advantage by lobbying, PACs, propaganda, owning the news stations. Joe Biden and Donald Trump both have lavish dinners with donors and business owners who discuss politics and national policy. And because these business owners are from Microsoft and Raytheon, they further America's goals (substitute America for any Capitalist country too). The capitalist class has centralized power because any individual in the class who tries to steer policy toward worker protections and limits on their own class are quickly out-competed.

I'm basing this analysis on some of the later chapters of Capital like Vol. 1, Ch. 25, Section 2 (I skimmed this just now to make sure I could word this response correctly). I do recommend the entirety of Capital for a scientific breakdown of worker power and commodity production. Hexbear has a reading group for the book going on now.

Read this

TL;DR: The growth of banks concentrates capital more closely, and also development causes the creation of truces between capitalists and mixes capitalist control between industries.