> Not least because in academia, either you teach, or you do research. You can't do both.

This is not true in general. In NZ, most academic positions are 40% research, 40% teaching, and 20% admin. Lecturers, distinguished professors, and everyone in between. Big research grants can provide temporary buy-out of some teaching, but it's explicitly part of the role, and not often reduced completely for long. Maybe 10% of academic roles at my university don't include research.

Yes, I don't understand that point either as all UK Lecturer job positions I have interviewed for (quite a few!) required at least 40% of teaching.

A 40% teaching is the most research-intensive contract you can get at most universities.

Good departments will still let you enjoy a sane workload because they will allocate a realistic amount of that 40% for teaching preparation, marking duties, etc.

I see what you're saying, but 60% of time spent doing something else than research, is not a research position. That is no way to be productive as a researcher. The upshot of this is what I point out in my other comments, that you end up offloading the research work to PhDs and post-docs while you take the back seat and of course keep the funds coming so that they can do their job.

... although my PI didn't :)