This situation probably did not happen overnight. It was probably a long process driven by feedback loops. Some students started cheating, so profs made classes

This situation probably did not happen overnight. It was probably a long process driven by feedback loops. Some students started cheating, so profs made classes harder or assigned more work to ensure that students learn enough to get jobs/scholarships/grad school admissions. More students started cheating. Profs responded the same way because of organizational pressure. Ten years later, courses involve obscene amounts of work.