Here is where the BS comes in. Look at this graphic. The crossover from Homo Rhodesiensis to Homo Sapien, is it gradual? According to this graphical "gem" all of the Asian and European H. Rhodesiensis died leaving a small group in Africa which MAGICALLY morphed into Homo Sapiens. Do does this morphing happen so quick there is no cross over fossils, we just assume there is for the sake of the theory?
That is a fascinating graph. Look what a small percentage of Rhodesiensis it took to evolve into Homo sapiens, which then took over with all the others slowly dying out. Whatever it was—massive radiation bombardment or more probably a change in conditions that favored intelligence of some kind, probably technical intelligence—it was dramatic.
These changes start to build on one another at a certain point too. Once smarts comes into it, Katy bar the door.