They are talking about POS in ethereum since years.
And now the PoS chain has already launched and been working great. Next step is just to move the PoW chain to it. But they are definitely going slowly and safely. And it is definitely a slow process. :(
It's pretty bad that Bitcoin still hasn't started working on it.
Their mainnet PoS network went live last december. The aim is to turn off PoW next year.
The recent activation of the beacon chain (and ether staking on it) means that they're committed to proof of stake now. All currently staked ether would be stranded otherwise.