If they need it, they probably can't evaluate it. The university, then, represents learning to individuals and knowledgeable individuals to society. The ability of the degree to shelter these activities from close scrutiny, immediate justification, and micromanagement helps provide society with more diverse and versatile candidates than it knows to ask for. If every detail of a student's learning were held to public account, a lot of valuable experimentation and improvisation would probably disappear. The degree's misrepresentation thus puts slack in a system that might otherwise be too taut.
Peers turn out to be, however, an equally important resource.
An early attempt at distance teaching by video revealed this quite unexpectedly. Jim Gibbons, former dean of engineering at Stanford, taught an engineering class to Stanford studnets and engineers from Hewlett-Packard. When it became impractical for the engineers to attend, Gibbons started recording the class and sending the video to the engineers. The engineers would watch these tapes as a group. At regular intervals they would stop the tape and discuss what Gibbons and the class were talking about, coming to some sort of collective understanding before going on.