Hello,
i've been thinking about how much energy proof of work stage uses why dont they just let it be proof of stake to use alot less energy, wasnt that the point? I've heard it may go up.

Monopoly have more chance of happening in proof of stake. Exchanges with huge wallets can generate more blocks using the user's funds. It is possible for someone to 51% the network by having half of the coins. Anyone can easily 51% the network by borrowing coins or buying the coins. Proof of work requires computing power which consumes energy and requires a lot of hardware which exchanges most probably don't have and is more expensive to carry out.