Exactly. The point is that if bitcoin crashed say to 1 cent then obviously the energy expenditure for mining new bitcoins will adapt to reflect that.
You can't say bitcoin is backed by energy because throwing more energy at the system will not necessarily increase its value.
I think it is a dead end to try to argue PoW superiority through energy expenditure.
It is used because the method is extremely solid for reaching probabilistic consensus with anonymous participants.
PoW is a means to an end just like the blockchain is. It should not be seen as something magical and be worshipped. It is a solid piece of engineering for a specific problem.