You say "centralized control" but that doesn't really mean anything. After all, the capitalist class already have centralized their power, and their class interests mean they structure every feature of both business and government to keep it that way. Socialism, as defined by a dictatorship of the proletariat, upends this class dynamic entirely. So no, socialism does not "require centralized control" just because a classless society would utilize central planning efficiency to meet societal goals. This is fundamentally, scientifically different from the current system of bourgeoisie control.

Basically, because socialism fundamentally requires centralized control, and I don't trust centralized control. I fully expect corruption and greed to exist, and to gravitate toward power.

Socialism is not a political philosophy based on belief, but simply the epoch that must follow capitalism, as it’s the first step in really resolving the fundamental contradictions of the latter—done halfway by the capitalist state apparatus, which aims to reconcile class contradictions whilst preserving their originator, and so itself falls into contradiction; the increasing socialization of production coming along with development contradicts the private ownership of enterprise, even still imperialism lends to the centralization of production/distribution as a resolution of the fall of the rate of profit (and this rears its head also in the sphere of automation, where capitalist development requires greater and greater productivity for competition, and yet, the greater the reliance on automation (for extension of productivity beyond human potential), the lower the rate of profit becomes as surplus value/variable capital comes from human labor power—this contradiction is unique to capitalism as it holds exchange-value over use-value, and so the necessary outcome is the resurgence of use value as the dominant force with a mode of production which serves the whole working populace rather than a few profiteers).

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

Wrt socialism? Do you understand how material conditions work? Which "societies" as a whole deliberately appointed tyrannical megalomaniacs? "Entirely too often" means you have to name at least five.

How would you implement your progressive tax system without centralized control?

I don’t want shares of a company, I want capitalism to end.

The choice is theirs: they can give up their ill-gotten wealth directly (philanthropically),

This is wishful thinking, if you wish in one hand and shit in the other which fill faster.

or they can be taxed out of existence (peacefully), or they can be fined out of existence (criminally),

These two options are at the barrel of a gun, so violently. I don't know why you don't seem to get that. Whose guns you may ask. Theirs. So more wishful thinking.

or they can be guillotined out of existence (violently)

We're here. Please catch up. However pointless violence will get us nowhere. A proper revolution must have goals to upend the current system and replace it with a better one. Much ink has been used to model this more can be read about it at marxists.org

This is how the means of production is owned in modern society. Shares. The problem isn't the idea that corporations look after shareholders. The problem is that the workers aren't shareholders. Workers are compensated primarily with dollars; executive-level management is compensated primarily with shares. When the worker starts receiving shares of future profits along with their hourly pay, the major problems are solved.

This is a continuation of the capitalist system and would be a tragedy if we revolted and got this.

Edit: rewrote some stuff, I should be less glib you seem to be earnest.

They've already chosen to not do the first three. I hope your guillotine is sharp, you're on the schedule this week.

Surely you don't just mean that there are workers along with capitalist shareholders, right? Shares as a speculative asset are valuable in a context of expected growth, and any system based on endless growth towards no other end is going to produce conflict with out finite planet and its finite resources, as we're already seeing around the world. Co-ops won't save you from the basic contradictions of capitalism, and that's without getting into the need of capitalism to have a destitute lower class (whether domestic or abroad) or how even the co-op employees are really just overseeing their own exploitation in order to stay competitive (as we see today with co-ops). You need to challenge yourself a little more to think beyond the paradigm of liberalism.

When the worker starts receiving shares of future profits along with their hourly pay, the major problems are solved.

This is so unbelievably stupid.