You have no idea about the issues that are present in PoS coins. There is a reason why almost all the top cryptocurrencies use the PoW algorithm. PoS is vulnerable to manipulation and those who enjoy the majority stake can gang up and do whatever they want, ignoring the requests from the community. With PoW, doing so is near impossible. And also, try to find why Ethereum delayed the shift from PoW to PoS repeatedly. They had to postpone it indefinitely, because the best developers still don't have the confidence to make the PoS algorithm risk-free, despite working on it for many years.