That's only the case if the Bitcoin price is low. Each block gives the miner a certain amount of Bitcoin, so it's only profitable to mine Bitcoin if the cost of the energy used to mine that block is lower than the price of the Bitcoin the miner received. The higher the price of Bitcoin, the higher can the cost of the energy be before it's no longer profitable.

Yeah it's of course a balance. It depends on the difficulty, reward, and cost. The reward is constantly going down. I guess I just think there will eventually be a balance where it's only possible to mine with free/wasted electricity, but maybe not.

That depends how high the BTC bubble price goes.

At a certain point, mining BTC could be the only economically viable activity to do with electricity.