How Do Different Consensus Mechanisms (E.g. Proof-of-Stake) Impact the Role of the Mempool in MEV?

In Proof-of-Work (PoW), miners had control over transaction ordering, leading to MEV extraction. In Proof-of-Stake (PoS), the role shifts to validators and block builders.

While the mempool remains public, the PoS mechanism, particularly with the introduction of proposer-builder separation (PBS), changes who can exploit the mempool. PBS allows block builders to specialize in creating the most profitable block, including MEV, which they then sell to the block proposer (validator).

This formalizes and potentially centralizes MEV extraction.