Yes, titanium is a big selling point for Helix. But I don't think it's "the whole point". For me (and I suspect for some others too), the titanium is just a bonus.
I think a lot of people might be interested in the Helix design (big wheels, small folded package) in steel or aluminum. Probably heavier, probably cheaper, but with most of the benefits of the original titanium bike.
Or would moving away from titanium make it necessary to do substantial redesign?