Alcohols are in fact added to many common gasolines to boost octane
rating.

no since 1930's hot rod engine. from then on until the mid 50's, benzene was
used by hot rodders. late 40's to early 60's AV/GAS was used for those engines
needing unusually high octane rated fuel. Mid 60's on to mid 70's the gas
companies sold the hot rodder's fuel. By the mid 70's, insurance company rates
killed the need for high octane rated fuel.