A material that converts pressure to thermal energy is an interesting concept, but wouldn’t that make it consumable? I think we do OK now with simple insulation (rather than active heating) if we could make it incompressible. On the surface, the new materials do perform and fit better than Rubatex. I think the analogy of a house works here. The first place to fix is infiltration or water circulation in a wetsuit. Second is increasing insulation values. Since solar gain doesn’t apply, third is improving efficiency of the active heating system — currently that is the diver in a wetsuit, waste heat off the generators for most hot water suits today.
I still have a sample of this material from the early 1970s — a blue gel-like material that was incompressible to thousands of feet. It is still very flexible but really heavy, like about 35 Lbs/Ft³. I don’t believe its thermal properties were as good as Rubatex. I can’t say why it never found a market but Dick Long of DUI might remember.
When it comes right down to it, most innovations in this industry are dependent on break-throughs in materials science and electronics. It just isn’t a big enough economic engine to drive innovation at that level.