Sit and kick wrote:
I think he is correct actually. In reality no material will have 100% energy return, but physically if such a material existed you could just bounce along.
Yes, with the additional and massive caveat that even with 100% return, you also need to have sufficient energy storage capacity to provide all your forward movement. That's the biggest difference between ZoomX and Boost, not the higher percentage of energy return, and it's also one of the biggest reasons to limit stack height. Shoes return energy very efficiently now, but they can still only store a small fraction of the energy necessary to move you forward.