Centralized on what layer?
If pool decentralization is your goal, new (or revived) pools constructing blocks with low rewards isn’t going to attract any meaningful hash power. It’s simply not economically rational for anyone involved.
More pools competing on rewards, features, and specialization is the only way.
If block template decentralization is your goal, then let’s focus on finishing the SV2 spec for block negotiation, and make it easy for pools & miners to use. The big pools will happily pass that regulatory risk off to the individual miners.