You have 0% energy added by having one Model x/S. How impractical it is, fine: but, the fact you might be able to do it in the future gives model y’s cars the better decision over one Model X/S
Huh? Maybe you're not understanding that a Y towing a Y is netting you fewer total miles in the long run than just driving a single Y. There's no reason to do what you're proposing.
A simple exercise to prove this to yourself: if you have a full Y and an empty one, how much range do you get when towing the empty one in Regen mode? It's less than half of the full range. And when you switch to the one that had been towed? Yup, less than half your full range.
