As franky1 has pointed out, there are certain rules that the miners have NO CONTROL over. For those rules, it doesn't matter how much computing power they can control. They could have 99.99% of all the block hashing power in the world, and if they tried to break any of those rules, ALL of the remaining 0.01% of the mining power AND the non-mining nodes, merchants, and users would simply ignore every block that they created.
Thanks, that is really helpful.
I think my misunderstanding comes from me confusing two very different topic. The rules VS the miners (asics) controlling more than 51% of the network's mining hash rate.
Both or your response are helping me make sens out of this complexity. I am far from technical genious, so I am just trying to make sens of this.
anyways, pools cannot change the rules by just sending a funky format block.
but here is a list of some(not all) things a network majority hashrate mining pool could achieve:
- ignore transactions of certain government black list/sanction list of known funds from certain countries/entities
- ignore transactions of certain government black list/sanction list of known funds to certain countries/entities
- ignore transactions of certain known funds to certain unregulated, unregistered services
- empty block (no transactions at all) just to annoy the network, cause mempool congestion
- ignore low fee transactions but only include extreme high fee's
- ignore lean transactions but include extreme bloated transactions
- ignore all transactions but include their own bloat, spam transactions with high fee, at no real fee cost as fee comes back to them
- re-org latest blocks by going back to previous blockheight and re make old height blocks with different/less/no transactions included
- build faster list of solved blocks but only release 2 at a time if competing pool built 1 block ontop of theirs, to remove the competitor block
Thank you for the time you put in this response.
Reading this list got me to learn things I was not aware...or flat wrong

Definitely will go back to this !