I have seen this: What’s the block reward for smart contract miners? Which addresses it for the POW period of Ethereum, but what about POS? They just earn a sort of "interest" for their stake as staking rewards, so why can't they just ignore all of the smart contracts?
I also saw this: How do miners profit post-PoS, if at all, how will new miners get their start, and who will execute the EVM byte code (and why)? but it doesn't say why the miners don't ignore it.
The role of miners goes away in PoS and is taken over by validators, people who stake funds and then find the next block through mining. The difference is, the validator (who is chosen at random for fairness and to limit collusion) is not competing with anyone else to find the next block. Thus, only one person / machine is burning electricity for each block period (currently every 15 seconds), instead of the whole world burning electricity.
However, the chosen validator must still run contract methods / tx's, that are part of the new block, and all other nodes must also run the same tx's to verify that it's a valid node and the resulting Ethereum state is valid.
