According to the "Pump" movie (not sure what their sources are), at the time cars were designed to run on various vegetable oils and (mostly) ethanol (e.g. the

According to the "Pump" movie (not sure what their sources are), at the time cars were designed to run on various vegetable oils and (mostly) ethanol (e.g. the Diesel engine was originally designed to run on Peanut oil), and it was actually a Rockefeller initiative behind the curtains to make sure that there is actually no competition for gasoline. Have not tried to fact-check yet, could be completely wrong - but if it is true, it's certainly an angle to prohibition that I was not aware of.