Most people who are holding and using Bitcoin don't give a rat's ass about how miners make their money, so long as transactions are reliable and cheap enough and so long as the value of Bitcoin grows, they are happy.
Miners on the other hand care passionately about the particulars of the PoW algorithm, and they also care about Bitcoin growing in value.
Therefore, holders have a natural advantage over miners in the negotiation process.
I propose that Bitcoin should transition to a decentralized PoW algo, a little bit at a time. First 1 out of every 6 blocks, then 1 out of every 5, and so on and so forth, over some period of time.
Once we have a decentralized PoW algo, then hashing power may be used as a fair voting mechanism for other changes.
I believe that the chain which is moving in the direction of PoW decentralization would be strongly favored. The miners will be dragged along as they follow their short term interests, as they always seem to do.