In a PoW environment you can take some of your coins, 'stake' them by buying a share in a mining pool, and then 'un-stake' them by selling your share in the mining pool.
The only difference is how much coal is burned and e-waste is generated along the way.
In both cases control and reward go to those with the most resources to deploy within said system.
> In a PoW environment you can take some of your coins, 'stake' them by buying a share in a mining pool [...]
Playing devil's advocate: there's a small but important difference in that, for PoW, you can "stake" coins from outside the system (for instance, by buying an ASIC miner with real money), while for PoS, the coins you "stake" must come from within the system itself. That is, PoS is a closed system.
The PoS system keeps value in the system. PoS also has more ability to reduce influence of malicious miners/validators by slashing what is needed for a bad validator to continue to participate.