Your history isn't really right here:
> Colleges started out as vocational schools for priests
There were three advanced schools (~graduate departments) at the typical medieval university: medicine, law, and theology.
> For much of American history colleges were places for farmers or engineers to learn their crafts.
I'm guessing you are basing this claim on the Morrill Act, which was to "provide colleges for the benefit of agriculture and the Mechanic arts."[0] It certainly doesn't describe the earlier American colleges like Harvard, Princeton, Yale, King's College (later Columbia), etc.
But even the state colleges that were founded with the help of the Morrill Act typically had loftier ambitions than acting as craft schools. e.g. from the inaugural speech of the founding of the University of California:
"The University is the most comprehensive term which can be employed to indicate a foundation for the promotion at diffusion of knowledge--a group of agencies organized to advance the arts and sciences of every sort, and to train young men as scholars for all the intellectual callings of life." [1]
But surely schools like Texas Agricultural and Mechanical were founded from the beginning with a focus on those practical skills? Nope: "Despite its name, the college taught no classes in agriculture, instead concentrating on classical studies, languages, literature, and applied mathematics." [2]
[0]: https://www.archives.gov/milestone-documents/morrill-act
[1]: https://oac.cdlib.org/view?docId=hb267nb0qk&brand=oac4&doc.v...
[2]: https://en.wikipedia.org/wiki/History_of_Texas_A%26M_Univers...