Or it fails as many on HN predict in which case you have nothing to worry about because this electricity usage would only be temporary, no miner would spend energy securing an unused blockchain.
And value is being generated, because Bitcoin is currently inflationary. The inflation is exactly the block reward that is being forced, through the economics of it, to be "burned" in electricity. If that were all that were going on, Bitcoin would drop in value accordingly. But, for a decade now, that hasn't been happening; the increase in market value represents the value being generated.
My point is that the economics of the situation means that the electricity being consumed is already in equilibrium with the value being generated, and will remain so.
[1] Plus the value of the transaction fees paid in each block, but that doesn't really change the economics here. The reason it's pegged like this is simple: mining is profitable as long as the electricity purchased still results in a return, which provides the upper bound. Spending less leaves money on the table for other miners. So the price of electricity consumed stays in equilibrium with the fiat sale value of the Bitcoin mined.
I don’t say to this to argue that the energy consumption either is or is not worth it, just calling attention to a gap in your logic here.