I don't know about there but here it was not the oil companies promoting ethanol (although they may be now). Congress (catering to environmentalists) is who did by creating the Renewable Fuel Standard in 2003. The idea being it could reduce greenhouse gas emissions, and to a very slight amount reduce our dependence on foreign oil. From this act a mandate to blend ethanol into gasoline was created and the ethanol industry boomed!
In digging around I found: Existing fuel producers and refiners, companies such as Shell, BP, and Exxon Mobil Corp., were caught flat-footed by the explosion of growth in the ethanol industry. A quote back then from Rex Tillerson at a 2007 Houston energy conference "I don't know much about farming, I'm not an expert on biofuels, and there's not a lot of technology I can add to moonshine," and "There is really nothing we can bring to that whole issue. We don't see a direct role for ourselves with today's technology."
It wasn't long though before the ethanol industry ran into financial problems and many went bankrupt. That left a good opportunity for distilleries to be bought for a fraction of what they had cost to build. This is when oil companies started buying them up, "if the government is mandating us add alcohol to gasoline we may as well produce the stuff ourselves". Now many, or maybe most, are owned by oil companies. Personally I don't care if they offer gasohol (although I think it's stupid) as long as it's not government subsidized and we have the choice of buying straight gasoline.
There is a chain of gas station / convenience stores in the northeast called Sheetz and as of 6-7 years ago they started offering ethanol free 90 octane (about 95 research) for about 10 cents a gallon over 93 and that's what I generally use in motorcycles, especially now toward the end of the season. I use ethanol free exclusively in the small engine stuff like mowers, saw, UTV's, generator etc all year. For the car and truck I can't tell any difference, it's fine in vehicles that are used regularly and alcohol is used to boost octane. Adding 10% ethanol to 90 octane gasoline is how they make the 93.
I haven't heard of problems in recent years with newer engines in fact everything I have says 10% ethanol is ok to use, Older engines are a different matter. As mentioned it doesn't store well either.