When you talk about a dual-fuel vehicle; able to run 100% alcohol or 100% gasoline, or any mixture; or even LPG (which would really be a triple-fuel deal) you are talking about a phenomenally complex fuel system, whether you are talking about a carbuerated or injected engine. You’re talking about a multi-thousand dollar incremental price change.
I think it would be fine to go say a 3-4 year “no changes” theme for most cars and certainly trucks, but much beyond that and we might as well go all the way over to reissuing Trabants and Yugos.
Lefties want us to use oxen. They’ll eat any bio fuel. Safe too!