Its a somewhat complex equation.
The ski stiffness contributes some directly but mostly by holding a tight arc: noodles, fat skis and non-cambers cant hold an arc tight enough. They will over-bend, wash-out etc
Tightness of the arc needs judged in relation to the speed, of course as well as the ski. A SL ski in a GS turn will result in less of a contribution to rebound. Sitting on the tails won't bend the tips etc.
Snow condition matters a lot: Soft snow won't hold a tight arc.
The body does help, by storing energy and even pushing or just resisting, at the right time (vaulting).
The timing matters a lot : You can spend too much time on the outside ski and kill the rebound or release too early and not let it create. You bave to release at the right time to use the bottom of the turn and it depends on many factors even for the same turn - the bottom of the turn is nit absolute, but in relation to the impulse of the upper body entering that turn... otherwise the resulting forces are in the wrong direction.
The usage of the body matters a lot: You can relax the wrong parts at the wrong time and loose vaulting etc. Flexing the release with a good timing, will allow the lower body to receive the energy and feels stronger, as there is less mass to be impulsed. Counterbalancing, angulating hard for instance allows the body to contribute to the rebound more etc.
You also have to put it in context - if it felt like one foot, it was one inch!