I don't think it is as simple.
GA developments are led from the USA and they are looking for a single fuel which is good for the whole 100LL fleet. They need that, because they have lots of people who fly distances in high perf planes.
They also have loads of bimblers but that's OK.
In the UK, you have a sub-community (very active on the forums) which can run on car petrol and they have small tanks which can be practically filled from jerrycans filled up at petrol stations. That community will continue doing what it is doing now. They don't fly to the bigger airports anyway because they won't pay more than £5 landing fee.
The "jerrycan" solution is utterly impractical for larger private aircraft. To fill mine up I would need a trailer full of heavy jerrycans, plus a bodybuilder to lift them. And no garage will let me fill up that many anyway. And mine is just a 1400kg MTOW 4-seater.
The oil companies would much rather sell a single fuel, and I suspect they are also waiting for whatever comes out of the USA.
France is a different case again. There is almost no French-pilot touring there; they have an almost wholly club based scene where people fly short distances from one club to another. They can burn something lower than 100LL in the Robins etc. But the airports there have the same dilemna as elsewhere unless they want to exclude foreign visitors, most of whom need 100LL because they are flying the more capable planes.