"Much effort was spent in trying to evolve fruit flies into something other than fruit flies. The effort was fruitless"
Fruit flies are used in genetics experiments to understand how genetic mechanisms work. They have speciated in the wild and in the lab, so that also shows evolution to be true.
The effort was not fruitless. Creationism is simply fruitfilled, rotten fruit at that.
For example, it is suspected that the Apple/Hawthorne Fruit Flys are undergoing speciation in the wild at this time.