The FAA had plenty of options to replace 100LL for decades but didn't have the balls to make any compromises at all. Most of the aircraft could have been trivi

The FAA had plenty of options to replace 100LL for decades but didn't have the balls to make any compromises at all. Most of the aircraft could have been trivially run on 93UL or even automotive 93 and the few that couldn't could have been trivially modified. It was politically untenable to subsidize any upgrades to the GA fleet and/or airport facilities, however, so they dicked around for an eternity and eventually someone came up with a more expensive cocktail of random other chemicals.