PoS dead? Did you mean to say PoW is dead?
They had to put those next to each other on the keyboard. Fixed.
I'm not making a prediction, I don't know that it's even 25% likely. But if it's 10% likely it's trouble.
The only things that matters in a blockchain are decentralization and the security, censorship-resistance and trustless environment it brings.
The resource cost is also a pretty big deal.