Correct, it's going to be a slow, stepwise process. But being about to take the first step is undoubtedly the main reason for the current price rally.That might be true, but we're still, long, long ways away from any sort of PoS happening. I'm running the node for testnet right now, and if that goes ok, then Phase 0 comes. Yes you can stake but once you convert Eth1 to Eth2, you won't be able to pull your Ethereum out until late 2021(maybe even 2022).
There are going to be something like six phases. Full transition doesn't happen until after that, which I suspect won't happen before 2024 assuming things go smoothly. Meaning PoW in some form will exist until then.
Revolution never happens as a jump. It's steady like everything else.