Bitcoin miner is a perfect money printing machine. Electricity goes in, money goes out. This simple fact overwhelms everything else, and ensures that Bitcoin will always use a lot of electricity.
If bitcoin
always uses proof of work, then you are correct because proof of work will always use a lot of electricity.
But generating heat with electricity does not necessary means waste. The heat could be well used in future when the competetion will go to the point only the miners who sells/monetarize the heat can still turn profit in Bitcoin mining