We're working on it, slowly but surely. This has been a known problem for a long time, at least since 2009 if not earlier. GAMI's G100UL was approved as a 100LL replacement in 2022, but there is still some controversy.

Avweb has done a good series of videos on this. There were some real engineering concerns and some typical aviation conservative decision making. But really, it's a tragedy of the FAA fumbling the ball for decades at this point.

https://www.youtube.com/watch?v=9F-WngVMJBQ

https://www.youtube.com/watch?v=Mvse4Xhzwuk

https://avweb.com/features/unleaded-avgas-airport-playbook-l...

https://avweb.com/aviation-news/judge-denies-g100ul-motion/

https://g100ul.com/

There's an equal and opposite person who'll be screeching about safety if you try and monkey with the fuel.

That's exactly why this is taking so long. There's no free lunch.