[VadeRetro]

The point being that surely someone should be able to make a fruit fly change evolve into something other than a fruit fly. Yet it hasn't happened. Why?

It's because of where you're setting the bar. To stop being fruit flies, a population would have to speciate, genus-ate, and then family-ate.

Fruit Fly:

common name for any of the flies of the families Tephritidae and Drosophilidae.

It might have to actually go a taxon higher than that (order), since the term "fruit fly" encompasses two families now. Speciations have been observed. That's more than what creationists usually admit as possible.

[DouglasKC]

It's because of where you're setting the bar. To stop being fruit flies, a population would have to speciate, genus-ate, and then family-ate.

I'm setting the bar too high? So? What's wrong with the concept of a fruit fly turning into a fish over thousands and thousands of generations? Isn't that exactly what millions of other animals are supposed to have done on their own?