Miners need not only to spend money on hardware, but also the upkeep of earning money by mining is expensive (electricity, or the cost of electricity generation).
Thus, Proof of Stake let the rich grow their richness for doing nothing. In Proof of Work they need to continue working to make their money grow. Not to mention that they removed the miners from the equation, proving that in ETH system the poor and the people don't have power at all, whereas in BTC no one ever had any such power.
Thus, Proof of Stake let the rich grow their richness for doing nothing. In Proof of Work they need to continue working to make their money grow. Not to mention that they removed the miners from the equation, proving that in ETH system the poor and the people don't have power at all, whereas in BTC no one ever had any such power.