Most mathematicians prefer research to teaching. Some absolutely detest teaching and hate the fact that they're forced to do it, while some rather like teaching and just wish it didn't take up so much time, but pretty much all of them would rather be doing research.

So the idea of employing a full-time lecturer seems quite appealing -- let the lecturers take care of all the boring crap like teaching freshmen how to integrate, and leave the research to the professors.

But wait! What if the university starts to figure out that they can get all their teaching done waaay more cheaply just by employing full-time lecturers? Professors have been doing well for the past few centuries by selling the idea that only a researcher is qualified to teach at the highest levels, and hence that they should be allowed to spend most of their time thinking about mathematics and only be obliged to teach a couple of classes a year. Full-time lecturers threaten not just the jobs of mathematics professors, but the entire future of global mathematics

So I can definitely sympathise with this view.