Be interesting to see how much more green 100 costs. In North America, refineries don't classify 100 LL as a "fuel" it is a "specialty chemical" because of the low volumes. This tiny demand and the need for a dedicated separate distribution system will IMO drives the price up which reduces demand which leads to further price increases to cover costs etc etc.
Jet A powered certified piston GA aircraft is IMO the only viable long term solution.