Better tools. The Neanderthals seem to have been reasonably intelligent but for some reason their tool-making skills remained static for hundreds of thousands of years, while humans made comparatively rapid advancements.
Neanderthal demise remains an enigma. Bigger, stronger, with more cranial capacity? Large displacements can be explained, but to vanish? With so many unpopulated places on the planet, it is unfathomable that they did not survive somewhere.
So that explains my roots! I have always been considered by my friends as exceptionally intelligent, but I have trouble working this computer, not to mention changing out sparkplugs on my car and repairing a broken water line. It's my tool using skills, that's what it is. Oh happy day! Now I have my excuses. I must rush and tell my wife, who does all the maintenance work on the car and around the house,after making certain that the beer and chips are put within my reach before I settle in to watch football and golf on the television.
The Neanderthals had exceeded their credit card limit and could no longer afford Black & Decker tools.