Earlier quoted context omitted.
> proof-of-stake rewards those who already have enough to stake As opposed to people who have money buying mining hardware to make more money that can be invested into mining hardware?
Yes, that's how most businesses work. You start with a capital investment, often times through a loan, and through smart management, make a profit on the margin , that you can choose to reinvest to stay competitive. Proof-of-stake is completely unlike this. People who "have" are not required to exchange any effort to reap new reward. They retain purchasing power while the "have-nots" lose purchasing power. I dunno if…
Entry costs in PoS are significantly lower; you just need a consumer-grade computer, broadband and the electricity to power a consumer-grade computer (i.e. of the order of 100 W). In PoW, you need specialized equipment (ASICs), larger amounts of energy (of the order of 1000s W) and broadband, this equipment will also need be renewed every few years.
The minimum stake of 32 ETH (in the case of Ethereum) can be avoided by using pooled mining, so that's not a true barrier of entry.
Being a validator still requires effort, you need to set-up and maintain the infrastructure and guarantee sufficient availability (higher than 2/3 of the time) to avoid being penalized. As with any economic activity where there is ample competition in the end the profit margins will be quite thin, so presenting this as free-money for the "haves" is just dishonest. If staking rewards are too high, more people will be tempted to stake, reducing the staking rewards, if they get too low some people will be disincentivized to stake and stop doing so, raising the rewards. This will tend to balance around just marginally profitable. This also happens in PoW mining. Main difference being that due to the low entry costs in PoS this economic activity is accessible to a much larger amount of people.