You've misunderstood something about Bitcoin if you think this is true. Bitcoin miners use resources based on the logic of competing with each other for the value of the mining reward, not based on the number of transactions they process. If Bitcoin solved all its scaling problems so that everyone in the world could use Bitcoin, but mining rewards remained constant, the resources the miners expend to collect the reward wouldn't be any different from today.
That's not quite true though is it? They could certainly (for instance) block transactions and generally hold the whole thing to ransom.
You're right, it doesn't have the financial incentive that you could (for instance) steal coin, but you could potentially block all transactions that don't have a considerable fee, for you, or just break stuff. Motives to do that will become more pressing the higher value the network is to nation states.
As more miners join, more power is used. But at the same time, miners could be removed, and hash capacity lowered, and the number of transactions per hour would be still the same.
So: energy used: number of miners. Transaction capacity: block size.
Both things are orthogonal. One number is independent of the other.
Right now the protocol is being updated to increase transactions per hour, and this has little to do with the number of miners.
To resume: if the world's economies ran on Bitcoin, because of some big transaction capacity increase, then the energy used would be about the same, because miners would be about the same.
Energy use in Bitcoin has no correlation with number of transactions processed.
And we'd have to, to keep bad actors from doing similar. It's a terrible idea!