Earlier quoted context omitted.
Before college was a means to get a job, it was status signalling for the upper class by showing they could spend 4 years not working and learning things with no economic value that few could afford. There was never a time when a large portion of society went to school past 18 for any reason other than economic or status gain, and why should they?
Economic OR status gain is putting a lot of work on the or. We've put into place a context for intellectual achievement at scale. Why shouldn't status be apportioned to someone who is recognized by a panel of peers and teachers to have useful insight into their field?
Because many "fields" in colleges are not useful.