Back in the day- almost 100 years ago- they added lead as an octane booster and also it helped non-hardened valve seat longevity tremendously. Well that was nasty and it killed cat converters so it had to go. MTBE came and went for environmental reasons too.
Wiki says ethanol may have been our oxygenate additive since the '20s were it not for political reasons.
Tetraethyllead - Wikipedia, the free encyclopedia
At any rate, it seems 100% gas is not a viable way to go.
The rest- energy conversion and food- come on.
