I think they will keep kicking the POS can down the road for as long as possible. POS kills coins because miners don't support it. Like it or not, miners keep this whole thing going.
You say that but there are a lot of top 100 coins that are solely proof-of-stake.
I am not sure the "miners keep this whole thing going" argumentation actually still has a leg to stand on. If you have enough people running a staking wallet (or a masternode for that matter), a network can hold its own pretty well...