This is really a great progress of technology. PoW is really not a rival of PoS.
At the beginning of 2018, PoS was really hard to compete with PoW because the amount of money to bet was too high because the price of altcoins at that time was too high. Pow will be more beneficial when the digging machine is quite cheap.
but now things are different. Safe investors will often choose PoS to place bets and they will have fairly stable monthly interest rates.