This is a massive over-simplification of the problem. A strong proof of stake construction has to consider all forms of Sybil attacks, all forms of wealth conce

This is a massive over-simplification of the problem. A strong proof of stake construction has to consider all forms of Sybil attacks, all forms of wealth concentration (a significant problem in most cryptocurrencies - the top 3 exchanges often hold more than 30% of the supply of the token), low participation rates, outsourced participation (most large crypto holders hire the same small set of groups to do the staking process on their behalf), among other significant issues. It's a hard thing to get right.