If you read books about pre-history carefully you will note something very interesting: all our ancestors were stupid.
It took them hundreds of years to realise that the plants they ate daily could be planted near their homes/caves. It also took them hundreds of years to realise that if you put a barrier around your home you can keep wild animals out.
Of course, we moderns are very clever. Just look at how far we've developed technology in the past 200 years?
But did it take 1000-6000 years to develop farming? Or does the idea that it took so long just play to the arrogance and egos of intellectuals?