I think there are some odd accidental assumptions in the question. For the U.S. system, although there is substantial drift in the last 10 years, the idea was not only that people should teach what their best judgement indicated, without worry of censure or loss-of-job, but that also their research/scholarship should reflect best-understanding rather than politics... especially given the transience and partisanship of politics.
There is also the idea that in otherwise-profitable enterprises people might not want to put any effort into teaching at all, thus not want to participate in a "university" (with students), without an otherwise-extraordinary promise of more-or-less-endless job security. Some smart, able people, not terribly interested in money, beyond a certain point, can be ensnared by the "care-free" aspect of a tenured faculty position.
"Even" in the U.S., in recent years there has been a push to "contract" faculty positions, indeed. In happy times, these seem to be no worse than tenured positions. However, obviously, in the next economic downturn the administration will have the easy option of terminating as many contract employees as seems convenient.
Yes, this is part of the increased corporatization of U.S. (and other) colleges and universities. Of course, we should understand that we are at the end of a sort of "golden age" between the pre-WWI times that only the upper-classes' children "went to college", apart from seminary students, and after the post-WWII time where the "GI Bill" financed returning veterans' college educations to avoid flooding the job market... which was already in disarray after all the women who'd been "allowed" to work in factory jobs and such in wartime were expected (or forced) to quit and "go home"... so there was an artificial surge both in the numbers of college enrollments and in the socio-economic goals.
And more complications currently...