If the miners are financially motivated and rational they wouldn’t refuse to mine the most valuable fork. They have a large investment in hardware and would los

If the miners are financially motivated and rational they wouldn’t refuse to mine the most valuable fork. They have a large investment in hardware and would lose a lot of money. If for some reason they did refuse, or worse, attacked the network (with double spends or censorsing transactions) then the users could emergency fork to change the proof of work and attract new miners.