It's going to take along time for ethanol to be removed from gasoline. The interested/affected parties include farmers, equipment manufacturers, oil companies, auto manufacturers, environmentalists, and they will lobby Congress for years. Then laws will need to be changed (not something that usually happens quickly).Then there will be a phase in period of a couple of years if the change actually goes through.
Add the fact that Congress can't get out of it's own way, and well, I won't be holding my breath.