EPA and their non-government activist brethren are clowns with ambition beyond reason or likelihood. That's also without doubt. FAA has authority over aviation and keeps them under control. Lycoming is just trying to solve a long term commercial problem ASAP - who can blame them, but they don't regulate aviation fuel, and neither does EPA.
Looking at what the FAA are doing right now, I have my doubts that FAA will be the champion for the light aircraft industry. If there is no change in administration (and even if there is, who knows what ideas future administrations may come up with), I would NOT even half trust the FAA to put up more than a for show fight to save Avgas burning airplanes.
Certainly, EASA would be overjoyed if they could get rid of the troublesome hobby pilots (as they see anyone between glider and PC12 users) and concentrate on 100 person plus airliners finally.... Many of those people look at the system of aviation in the old Soviet Union with one state carrier and no GA whatsoever and like the idea just fine.
In most other places, Avgas is even today not really available. Prices in Southern Europe or Northern and Central Africa are horrendous, 4 Euros plus per Liter of Avgas, which would make it somewhere near 15 Euros/20$ per USG, where it's available. NO local CAA nor EASA have shown ANY interest in fighting this. Just the opposite, every GA plane which is broken up or goes to a museum is for them a victory.
Regulators today will "tolerate" ULM's or VLA's as they are mainly VFR and don't disturb the big guys. However, they do disturb a lot of anti aviation guerillia who live around just about every airport. The Avgas crisis is one massive chance for these people to do away with those hated planes once and for all.
So in my view, relying on today's regulators is like relying on the tax collectors to pay you rather than take from you. And the only way to get over the Avgas problem is to eliminate the need for "Special Fuels" altogether. Either we are allowed to use what is available at the gas station outside the airport, get sufficient pumps at the airports it self of that material, or we go Jet A1. Failing that, GA as we know it won't be there in 10 years from now.