When universities and colleges worked properly, or at least much better than they do now (which is 'hardly at all') - then they were vocational institutions.
Medieval universities taught that which was necessary for an individual to become a member of the intellectual ruling class (logic, grammar, rhetoric, mathematics) - and that was the vocational purpose of becoming a 'Master of Arts' (Magister Artium).
The Doctoral degrees were also vocational - both in a specific sense of educating for practice in Divinity, Law and Medicine - but also in the general sense of being a license to teach at Universities.
Post-medieval secular colleges retained the vocational focus: the aim early on was to teach what was necessary to become an administrator in that particular state - then later the vocational focus shifted to include that of being a generic 'teacher' of advanced studies (which at that time was mostly teaching in 'grammar schools').
When school teaching was essentially focused on the classics or mathematics, they formed the focus of university degrees - vocational again. To these were later added new vocational professions such as engineering, architecture, dentistry; and specialist teaching subjects, such as the sciences or specific arts.
Even as recently as forty years ago, most English degrees were implicitly vocational: the subject matter of degrees focused on either training for a specific profession, or for a specific type of advanced school teacher. The bulk of graduates were assumed to become high school teachers of the subject they studied at college.
(The apparent exception of historical US liberal arts colleges can be understood on the basis that they actually functioned as grammar schools not universities: they provided basic general education for elite administrators.)
Since the vocational link was broken, universities and colleges have been adrift without land in sight.
They claim to 'educate', but what is 'education' in practice?
By assuming that 'education' is valuable in and of itself, the concept has been emptied of substance.
Education is now open-endedly defined as 'whatever universities teach'.
Lacking any understandable vocational rationale for degrees, higher education makes implausible claims about its generic benefits.
However, the claimed effects of higher 'education' as such turn-out to be merely a combination of maturation and selection. Graduates (as a class) are three or four years older, and possess intellectual abilities according to the degree of selectivity of a particular institution.
Until age and selectivity are controlled, quantitative claims for the generic benefits of generic higher education are dishonest or ignorant (usually both).
(By contrast the specific benefits of a specific program of study are much more comprehensible - when present. The professional programs potentially retain this core rationale - but this activity constitutes a small segment of higher education - and indeed the professional courses have been corrupted by a bogus goal of 'generic education'. The fake rationale of non-vocational higher education has thus contaminated the obvious functionality of vocational higher education!)
Let's be clear: There are no generic benefits from spending x years studying something called a degree in some-subject-or-another, at something called a university.
Really - let's be sensible - how could there be?
Advanced formal education just is vocational - not in the sense of being a training for a specific job, but in the sense that it can cohere and potentially be valuable only when conceptualized as a preparation.