I mean, right now, the most private and least controlled means for people to buy things is with #fiat: cash.

I know, it's value is manipulated by the central bank, but that is a product of the banking system. If everyone held cash, then the Fed would be impotent. Cash itself is fundamentally decentralized in the sense that it doesn't rely on a central authority to handle organizing exchange; you don't have to wait for the check to clear when you pay cash. Moreover, whatever you buy is between you and the seller; it's not visible to anyone else.

Until a crypto technology can replicate that kind of privacy, then the state will always have an upper hand on controlling people through money. Hell, they can effectively steal your money by blacklisting it when they know you have it! That's an extremely effective means of control, let alone knowing what you're buying and selling.

From what I understand, #Monero is the closest at trying to solve this problem, but it certainly isn't the most popular.

In my opinion, this is the single most important issue that #Bitcoin has left to resolve. Until then, I hate to say it, but #Bitcoin is just a game.