> almost every large miner and bitcoin company wanted to change the protocol
If the miners really wanted to change the protocol, they would have done that. The exchanges would have followed, as they had declared that the longest chain would win, and that would be game over.
Instead the miners gave in to the perceived authority of the Core developers, who pinky promised to later raise the block size (which they backed away from).
The exchanges have no reason not to support both sides of a fork, for example the BTC/BCH split. Then the owners of the tokens ultimately decide which one is more valuable by selling their tokens on the chain they don't prefer and buying tokens on the chain they do prefer.
There is a very clear bias if one chain keeps the ticker, and therefore the price, so much that in practice exchanges exchanges can decide which chain "is the original one".
This. There's a bunch of waffling above about how the miners vs stakers will control stuff and so on, but in reality it's the markets which define which gets used. That's what decided the block size debate, not users spinning up nodes or miners pushing in one direction in ther other. Miners follow the market, and so will those running validators on proof of stake. Those who can influence the market have the most power here (and usually that's vocal members of the community or developers).
If the miners really wanted to change the protocol, they would have done that. The exchanges would have followed, as they had declared that the longest chain would win, and that would be game over.
Instead the miners gave in to the perceived authority of the Core developers, who pinky promised to later raise the block size (which they backed away from).