This argument in this article (tweeted out by Shit Academics Say) is just designed to pit one group of workers (sessional lecturers) against another (tenured faculty). This is because it ignores the fact that the number of faculty positions at least in Canada is kept artificially low.
Notice that there is no mention whatsoever of class-sizes. Coming from UofT, I can tell you, class sizes have been out of control for years. My intro bio class so big that no lecture halls could house it. Lectures were in the 1730-seat Convocation Hall.
Convocation hall is a beautiful building but it is designed for ceremony, not pedagogy. There is no chalkboard or whiteboard, and if there were, the students in the upper balcony wouldn't be able to read them. What's more the seats have no writing surface for note-taking.
More recently, I taught a "general interest" linguistics course (a "bird course") so big that it also couldn't be housed in a proper lecture hall. Instead we had what was basically a movie theatre. The lights were perpetually dimmed, and again, no chalkboard.
These sorts of non-classrooms really only allow for one type of teaching style, possibly the worst type: A lecturer droning on about a slide deck.
Beyond just the lectures, it's quite impossible for all 1000+ students of such a class to have direct access to their professors in office hours. There aren't enough hours in the day.
(Of course, most students don't go to office hours. It might make a good action, though, for student unions to organize students to go to office hours en masse. Not to shout slogans at professors, but just to ask for help)
Clearly, UofT, the largest university in Canada, has reached its capacity of students.
Imagine, though, if we kept tenure and the researcher/teacher model of academia and put hard limits on class sizes. Say, 200 for 1st yr classes, 100 for 2nd yr and so on. How would that affect things?
The neoliberal response would probably be "well, you'd have to have fewer students, probably only well-off white students."
But there's another possibility: Expand the faculty size by creating new universities.
This could mean founding a brand new university, or it could mean splitting up oversized universities. UofT, for instance, has three campuses: Downtown, Scarborough, and Mississauga. Why not spin them off from each other?
There are definitely ways to do this that I haven't thought about, and none of them are perfect, and all of them require public funding. But that's true of any societal problem.
But we can't really expect to solve the problem without an adequate diagnosis of the problem's source.
There's no shortage of qualified educators, nor is there a shortage of people who want/need an education.The problem is infrastructure.
So, whenever someone makes an argument pitting workers against workers, it can only really serve to obscure the fact that the problem is elsewhere—with management, with bureaucracy, with politicians.