Decentralization---CPUs----GPUs----Asics----ETH PoS---Centralization
Ideally in order to achieve the most decentralization possible. All of these devices/methods of securing the network would be useful to secure the network. In a perfect world.
I agree, decentralisation depends on which pool you choose and not if you use GPU, CPU, FPGA or ASIC. Ethermine has 28% of the ETH network, it's not due to ASICs.
https://etherscan.io/stat/miner?range=7&blocktype=blocks