If miners chose to mine on a chain that no-one wants, then everybody has to grudgingly go along with it, or cease to transact.
The longest chain is always the most valuable.
The longest chain is always the most valuable.
No, if the miners mine on a chain that doesn't meet consensus rules, users will not follow it. If miners decide that the coinbase issuance schedule isn't to their liking, and decide to revert it back to 50 bitcoins per block, users will reject those blocks. This is a fundamental governance property of a blockchain.
Yes, users can reject Hard Forks.
But the problem is that soft forks can do basically anything. Yes, even increase the block reward, in a roundabout way, (by using added extension blocks that have special rules, and then requiring all transactions to go through the extension blocks.)
Although from the perspective of a non-conforming Node, this would just look like a DDOS style mining empty blocks attack.
At this point the only thing that users can do is change the Proof of Work algorithm. .... But, if the big players in mining have a bunch of GPUs on standby... well, it is not even guaranteed that this will work.
From the perspective of people transacting on Bitcoin's infrastructure I suspect they'd call it "an attack."
You grossly underestimate the hashing capacity of the bitcoin network. The hashing capacity, at time of posting, is approximately 5,000,000,000 Gigahashes/second[1]. Spot measurement of the hashing capacity of an EC2 instance is 0.4 Gigahashes/second[2]. You would need 12 BILLION EC2 instances to 51% attack the bitcoin network.[3] Using EC2 to attack the network is impractical and inefficient.
[1] https://bitcoinwisdom.com/bitcoin/difficulty
[2] https://www.reddit.com/r/Bitcoin/comments/1btgl1/i_was_curio...
[3] x/(5e18+x)=.51 y=x/.4e8
Even most BTC users do not run actual clients anymore but use exchanges or wallet services which bundle huge numbers of users behind few actual Bitcoin network nodes.
I don't need to overcome the network, I need to invite the network to have arguments with itself, by finding a way to introduce widespread partitioning of the network.
In this, the preference to longer hash chains seems like a good idea in a unified clock model but a somewhat optimistic decision in a split clock world.
To do this you would need to have the equivalent hashing power of the network. Peers expect an nominally equivalent amount of Proof of Work for the difficulty adjustment. You would also need to guarantee that the peer connects to _no other_ peers
Your thinking is good adversarial thinking but it's already covered in the protocol.
Only the longest chain that users consider legitimate. If users reach consensus on using rules that have lower transaction costs, it won't matter how long miners mine their higher transaction cost chain.
The big question is: can users achieve such consensus politically, or in practice do the miners lead the users because they need less organization to do so?