For starters the price of electricity is not at all capturing all the negative externalities of generating that electricity. A miner paying a utility bill is not paying the entire cost of the energy used for mining.

Second, the vast majority of "work" performed by Proof of Work schemes is literally thrown away. It has absolutely zero utility and so is in the most literal sense just wasted electricity. Not only do they require waste but by design require increasing amounts of waste as the networks scale. They're not designed to improve or get more efficient.

Unless you're just running a game idly in the background, idling an SUV in the driveway, or idling a jet on the tarmac they're not wasting the resources used to run. They're serving at least some utility. An SUV or jet to Vegas might not be the best use of fuel for the task but they're not just wasting it. Neither an SUV or jet burns coal so even their energy usage has fewer negative externalities than a majority of blockchain miners.

Proof of Stake has been coming Real Soon Now to Ethereum for a few years now. It's still not here. Even with PoS it doesn't help matters if a majority of coins are still PoW and continue burning an Argentina worth of power.