I don't doubt that mushrooms and other natural nootropics helped; but, they
were would have been freely available to other creatures at the time.
However, I have heard that these mushrooms thrive in cow dung, and humans
certainly learned how to herd cows so that they might have had a monopoly
of the best mushroom supplies. Some species of insects, however, herd other
insects, and also use fungi as foodstuffs, or make honey (and perhaps other
psychotropic elixirs we are yet unaware of). Why wouldn't having these
similar 'self-owned' resources, and the cyberorganization that cultivating
them brings, have raised their consciousness as well? Anyway, I suspect
that any _Great Filter_ would likely be a complex mix of factors, rather
than having one 'magical' ingredient. No matter how self-directed a
creature becomes, it is still part of some larger system of resources and
restraints, and must adapt to that as well.
Mark