[Drammach]

Modern man could communicate and understand new things and ended up filling all the niches much better than the Neanderthals who were always protecting themselves from foreigners.

Consider that Neandertal isolationism from yet another angle, rather than just the economic-trade issue..

It may have effected them socially as well..
Neandertal may have practiced inter-marriage within the tribal structure and only rarely introduced new genetic material from the outside..
If this were "common practice", recessive genetic traits may have been passed from one tribal group to another, weakening the species..

For Cro-Magnon man, the "gatherings" may have meant more than opportunity for trade of obsidian and artwork, but also for finding mates outside of the tribe, mates that were not likely to be familialy related..
Greater genetic diversity and transfer would contribute to a flourishing species..

[expat_panama]

The 'experts' keep changing the story, but the last I heard was that intermarriage between Neanderthals and sapiens didn't happen, probably because it couldn't happen.  

But this gene pool stuff is really important.  Homo Sapiens are a very diverse group and IMHO we 'hard wired' that way.   I can tell you from my personal experience that whenever I seem some foreign chick I've always wanted to see what's in those jeans genes.