Lycoming and Continental are working on newer technologies to allow the new engines to run on any fuel, but the problem remains they are going to sell 4 of them, and while monopoly makes them drag feet somewhat the real issue is the small numbers of production- no matter what engine they produce. I do not see either company as a callous bullies with a strangle hold on piston aviation, more like a hobby industry that has a zero R&D budget. That plus the steep cost of certification testing for all airplane powerplants leads to the archaic state we have now. In addition to those blocks the other one is the incredible lifespan of the typical piston airplane. Where else can you find engines sitting around that are older than you are. Those engines have to be fueled, and they cannot realistically be retired as long as they run safely on 100 octane. It's going to take a drop in non-leaded replacement gasoline, plus a metric ton of years for all those high octane engines to be out of the picture.