In PoS the rich can become validator as long as they have money. The limit is money.
In PoW, they can’t buy gpu as long as they have money, because there is another limit that money can’t always buy, energy, resources, needs (gpu for gamers, researchers, etc)
In PoW, they can’t buy gpu as long as they have money, because there is another limit that money can’t always buy, energy, resources, needs (gpu for gamers, researchers, etc)