No, the miners don't decide what Bitcoin is. If a miner produces an invalid block, other Bitcoin nodes will reject it. It's true that the recent hard fork prop

No, the miners don't decide what Bitcoin is. If a miner produces an invalid block, other Bitcoin nodes will reject it. It's true that the recent hard fork proposals have keyed off miner voting, but they wouldn't have to - they could just activate at a certain time, block height, strawpoll vote API, or whatever.