Like it or not, some variation of PoS is going to dominate. The general opinion is slowly being aware that the money given over to the electricity and the hardware companies is better off being utilized to develop the coin itself.
No one is forced to give any money to anyone, people exercise their own choices.
Competition requires energy, no-competition doesn't.
So which of the competition is better suited - the one which is spending resources to keep the network running, or the other which is using the same resources in improving itself?
We might have a different definitions of improving.
Improvements in PoW come in a form of advancements in energy-efficient computation, new types of power sources and research of cryptographic hash functions. These improvements are tangible and can be applied to other areas of human life.
Improvements in PoS only benefit the few in power as any innovation will be privatized and used to further strengthen the control grid.
So you equate PoS cryptocoins to dollars...
No, I could use BTC instead of USD.
In BTC large coin holders need to decide what percentage of their wealth they will keep in coins and what they reinvest in mining so that competition for control keeps the system robust.
Investing the whole stake is risky as mining farms can burn or become obsolete as new tech emerges, so some balance need to be sought. This is what separates PoW from PoS. It is much more dynamic system without obvious asymptotes of power saturation. It is possible of course that PoS system stays robust and honest for a long time without spending any energy, but it's better to have alternatives where competition is more welcome. PoW provides that.