Yes, I believe that the lack of adaptability was their undoing, both in the novels and according to anthropological research, at least that's the hypothesis.
Welcome to the forum. We can use more members who are willing to fix their typos, as well as express their own original thoughts. You can edit your posts if you do it right away.
Say, Pandora, you're missing some great reading if you don't take the time for
Mammoth Hunters and
Shelters of Stone. They're on tape now, so you can listen while commuting if you lack time. Not only are they entertaining, but you won't be rotting your brain listening to rant radio.