Quite a few people. Including the most vocal advocates of ideological Darwinism like Richard Dawkins.
We are talking about biology today
And today, biologically, no one has been able to replicate the evolution of radical speciation in a controlled environment.
Noone expects to be able to. Evolution certainly doesn't say "radical" speciation is possible in limited time. You are confusing the theory of how evolution occurs with the fact that it has happened.
If we found a clear smooth set of transitional fossils from ape to man representing a generation at a time, would you accept evolution then? Or would you still demand that unless scientists turned a chimpanzee into a man in a lab it wasn't a fact?
Do you think craters on the moon were caused by meteors? Noone saw it. Noone can create a crater that size in a lab. So is it a fact?