“Scientists have been pushing the Out of Africa thesis a bit much. They wanted it to be true.”
No, they didn’t WANT it to be true; rather, they had to work up a theory based upon the oldest fossils found.
Here’s a theory: maybe you find the oldest fossils in the areas that never got scraped clean by glaciers because they never got scraped clean by glaciers, not because there were never any fossils as old anywhere else :)