Almost nobody has the drive necessary for completely unguided self-education, and even those people will inevitably miss some important things.
I believe that a college education (lectures and assignments, at least) can be replicated online. I just don't see that anyone's done a particularly good job of it yet. There are lots of bits and pieces floating around, but not much overall structure.
As a teacher, I like on-line resources as granular as possible so I can remix them and present them to students. My practice is then the 'glue' that sticks the bits together for the particular individuals I'm working for.
Do you think that direct contact with a teacher (motivation and confidence building in the case of Winer's post) can be replaced by some other model?