With PoS, every staker (on average) just maintains their fraction of the total supply. So PoS just enshrines the wealth inequality that exists at the time PoS starts.
Similar to how PoW distributes rewards: those with the capital to purchase mining power will reap benefits.
This model unfortunately also exists in stock markets and most aspects of a capitalist society. Arguably PoS returns in crypto networks may be slightly more equitable long-term as it is not a permissioned and closed-door system (validator queues cannot discriminate based on class, race, credit score, region, and family for example).
