One of the biggest errors? Possibly. But there has been a lot of competition of late.
Why? Because it makes no sense to "learn" primarily from others who know no more than yourself, who are equally ignorant about the world. This would be obvious for anything other than socialization, but our age apartheid system has been the norm for so long now that only a few older people remember that it didn't used to be this way, and that it doesn't have to be this way.
Also, it acts as a barrier between generations, cutting young people off from their own culture and their own history. It is the destruction of a culture and a people, if not the destruction of that people's genes.