Proof Of Work is ultimately a dead end due to the ease of attack on the network, DPOS is a bit more resistant but look at how easy it was for Justin Sun to take over Steem.
If some government wanted to tank Bitcoin right now they could, they could print billions or trillions of USD and just buy miners and 51% attack it. CHINA/USA are playing with infinite printable money here. Long term POW's fundamentals say it should go to 0, especially given super computers will be able to easily get passwords.