What encourages miners (all miners; regardless of how much hash rate they have) to include real time in the block and not to agree among themselves to include a time such as if it took them 10 minutes to create the block. I mean, it wouldn’t change the probability ratio of “finding the correct block and distributing the rewards” if all the miners together pretend they need 10 minutes (we just lower the necessary threshold). In that case, the miners together would mine the block in 2/3/4 minutes or less on average (I put a random number), and set the time in the timestamp as if they needed 10 minutes (of course, all the miners would have to wait before sending the block , in order to comply with the +2h rule). I can only see good for them here because in this way all miners would benefit greatly as they would spend a significantly smaller amount of electricity to find one block.
So, what incentive do miners have not to lie about the time it takes them to mine a block and to reject such an agreement?
