4. What methods do you think can be used to reduce the energy consumption of POW?
PoS is the solution for it. But are you going to settle for PoS when PoW is the most secured of them all? if you are for security, PoW is the key. But if not, then PoS is totally fine and if you're already rich then it's likely that you'd be richer with that.
The problem with POS is with centralization. All the token is concentrated in a single pool so if something happens with it the whole Blockchain can be in danger. Though it consum less energy and faster than most POW network but it's centralization problem can be a big concern in the future. Vitalik also said that the problem of eth centralization will not solve very soon.
Exactly.
But because of what they believe is right, they've pushed for it and it happened for ETH. And we're seeing more of these projects go into PoS because of their advocacy to save energy. Like everytime there's a PoW discussion, it's always the emission that they discuss like it's a curse that they can't getaway with it.