Is Proof of Work is going to lose popularity compared to Proof of Stake? Ethereum is going to PoS.

Is there going to be a lot of hash (computational) power idle because of shifting to PoS?

Where that power be used then? Will it address such decentralized computing projects as Golem, Storj, Sia, etc?

oh man, just WAIT

you ask an interesting question that i dont think many people have thought about
ETH currently has MILLIONS of GPUs on it, where does everyone think that hash is gonna go? it wont shut off, most people are priced in and over-invested
it will go to ANY other PoW coin, and their ALL gonna get SLAUGHTERED : / PoW will be effectively ded once ETH ends it imo
The hypers will say "PoS is the future", something others have been saying for years, and it's gonna be crazy times for those moving too slow that get caught up still hodling PoW coins
the GPU miners have yet to cultivate any coin or coins. they have been just REKTing projects until the asics take over the algo or the project DieS.
but if you look close enough a few good vertical feathers and orbs appear to be growing in the REKT cracks.
XMR moved down to CPU mining.