Until then, here's a good podcast episode interviewing George Braly, the man behind G100UL. [0]

Incidentally I recall a later episode mentioning that a couple of decades ago someone was able to get an unleaded fuel approved for aviation in, iirc, Sweden. Unsure why that didn't get much traction.

[0] https://aviationnewstalk.com/tag/unleaded-fuel/

Surely you mean "as soon as practicable." :)