You still need to make decisions in a decentralized system, I don't really see what alternative you're imagining that's even more decentralized than "start a parallel chain if you dislike it, let people vote with their feet". You can't really start a parallel USD to see if people like your monetary policy better.
And, obviously, this is political. Miners make a lot of money off the status quo, devs want to reduce the energy/environmental impact of their chain. Proof of stake takes away a moat that miners have built around their operation (now anyone with 32eth can be a validator). There's no way out of that conflict of interests without some degree of politics.
