The REAL Value of Bitcoin

i keep reading bitcoin has no value, except for what people assign to it. like if you can trade 1 btc for a loaf of bread that is btc value. guess what people that is how all the worlds currency works. all financial system are built on a house of cards. the usd is only as valuable as you make it. example the usd is suppose to be back by gold, which we all know it is not anymore. gold value derives from what people are will to pay for it. so lets the us federal reserve decides to put 1 ton of gold on the world market what would happen to price of gold it would plummet. now lets talk about the actual value of money as a whole. the us really owes china trillions of dollars, lets say china said i want all my money. the us can simply say no and war would ensue. the point i'm making is bitcoin has the best chance for every day people to control financial system and this scares the shit out of the government. i truly believe that people will realize this soon and all governments will have no chose except to get on board. now you say the government can just ban all crypto, but remember, in a free market anyway, it the people who have control of the government not the other way around. just remember their are a lot more of us then they are of them.

Okay, at risk of asking very ignorant questions:

I just spent the afternoon learning about how Bitcoin works, and think it's very cool and interesting. My question basically is: "Who's in charge?"

I know you're all clamoring to say "No-one! It's decentralized!", but there's a lot of standardized rules (eg. the amount of BTC the miner gets to add to a block, the number of zeros at the start of the hash you need to achieve for proof of work, the maximum accepted data size of a block). All these rules are ultimately enforced by the decentralized people/groups doing the mining. But who sets the rules? What if people stop following them?

Now, I can understand that if one small group starts ignoring rules, then their blocks will just be ignored and they'll get no benefit. And I understand that a lot of these rules were set from the beginning, so there's little dissent.

But with some very large mining pools, and the potential for changing rules (eg. the maximum block size, the number of zeroes at the start of the proof of work hash), who makes those decisions, and what if there's disagreement between major mining pools? Who decides?

Most importantly, I know some large mining pools have chosen to multiply to avoid having too much power over the blockchain, but is there really anything to stop a large mining pool taking over? Or large mining pools secretly working together to control the blockchain?

Final unrelated question: Currencies need to last for decades or more. As the blockchain grows, how can we be sure that it won't become unwieldy? If storage/compression tech grows slower than the blockchain?

Thoughts??