> I.e. These rules CHANGE, and since they change(and have changed in the past) if you can convince a majority, you can change the rules to be whatever you want.

False, everyone running a node is enforcing whatever rules their node is written to enforce.

You could have 99% of the hashpower, if you generated a block saying that Coinbase is handing over all their Bitcoin to you (with an invalid signature because you don't have their private key), their node and the nodes of most/all exchanges and businesses would just go "lol, wtf is this shit, not a valid block because it has a transaction with an invalid signature, ignored".

A majority of hashpower is not the same as a majority of economic participants.