Evolutionists object to the that notion also, that "major structural" changes happen within the evolution of a single species, or even consequent with a single speciation event.
We envision -- and more importantly have concrete examples thereto in the fossil record -- "major structural changes" arising over a whole series of species and speciation events. For instance there are fossils showing the migration of the ear ossicles starting out as large bones in the reptilian jaw, one actually functional in the jaw joint, and ending up as tiny bones in the mammalian ear. This is certainly a "major structural change," but it occurred by tiny steps distributed across many different species.
“Missing Link, or Just Jawboning About Ear Evolution?”
And the 'scientists' are REAL sure about this!