I would assume that even if they didn't use air suspension, that there would be a different target ride characteristic that would require different spring rates and shock tuning.
Without Lucid confirming or telling us, we will never know how much of the Gravity comes from the Air, but I'm really hoping they are pulling as much as they can from the Air into the Gravity and subsequent models. Tesla made this mistake with the S and X, as an investor I hope Lucid hasn't done the same with the Air and Gravity especially considering that Lucid is trying to cut costs to stay afloat.
In some way or another every car manufacturer has been pushing to do this over the last decade. Subaru has its SGP, Subaru Global Platform, Toyota has its Toyota New Global Architecture, obviously Tesla does this with the 3 and Y. Porsche has touted its PPE, Premium Platform Electric, for its future EV lineup. Even Ferrari is doing this, the new Purosangue is based on the Roma.