While still revolutonary, this makes more sense. I don't consider Homo Erectus as Homo Sapiens (Homo, yes, human, no), nor does anyone else in the field. Still, how did they get here, where did they go and why no remains?
1. They walked here.
2. They walked away.
3a. Who says there are no remains?
3b. Animals ate them.
3c. 200,000 years is a damned long time. The remains could simply have dissolved.
Anyway, if these were nomadic hunter/getherers you wouldn't expect to see much. Heck, there's not much physical evidence of such tribes that existed a few hundred years ago.