A Bitcoin miner that can 51% attack the network will need a huge factory full of mining rigs. A proof of stake miner who wants to 51% attack doesn't need that.
> Bitcoin needs a huge factory. ETH2 needs a billion dollars. I feel like a billion dollars could probably buy the factory you're talking about.
What you don't get is what comes after that.
In PoS, once you invest a billion dollars, you're set for life. In PoW, you invest a billion dollars but still have to keep investing more and more in order to survive. If you're complacent, a new upstart miner with innovative technology could swoop in one day with 10x more efficient mining method (it could take many forms, such as a closed source bitcoin node that does things much more efficiently yet still fully follows the Bitcoin protocol, or it could be a closed source hardware that they don't sell outside of their own mining operations, like Apple does with their own chips) This way the PoW network as a whole will keep evolving because of competition. In a PoS network there is no competition once you invest the billion dollars and it's a complacent network compared to a PoW network where everyone is constantly competing and comes and goes (those who can't keep up will get left out and leave). If you join a PoS network where someone has a huge stake collectively, you're basically joining a feudalist society where you're being ruled by a king. If you join a PoW network you're being ruled by entities that keep competing to show their competency. it's like the presidential election is going on for every block.
That or maybe just a few colluding mining pools. The network is only 'secure' because mining cartels own most of the specialised hardware, increasing difficultly. ETH 2.0 starts to pool all that power back abit, by allowing others to compete for staking rewards.
