There is actually a difference between being self-taught as you describe it, and being an autodidact. The latter is able to identify holes in his own knowledge

There is actually a difference between being self-taught as you describe it, and being an autodidact. The latter is able to identify holes in his own knowledge, and find appropriate material to educate himself on. That ability is what defines an autodidact in the first place. This is also the very same thing you get taught in basically all sciences: How to aquire knowledge about a subject matter you yet know nothing about. So, an autodidactic Programmer without a degree will most certainly have similar knowledge as a CS graduate, simple because that is how such people "tick". It's just that not every self-taught programmer is an autodidact. And in that case I agree with your argument.