"Economies of scale are a thing."
Yes, economies of scale are a thing. They generally cause average cost per unit of output to decrease, as total output increases.
As I said, for the $100k/pa cost quoted by the article, a single student could afford to pay for pay+tax+benefits for a 1:1 tutor, 20 hours per week.
Given that most university lectures/seminars/tutorials have a much larger student:teacher ratio, economies of scale should mean universities would achieve a much lower cost of tuition.
I get that universities do other things. I get that they need to build and maintain infrastructure. I get that they need to subscribe to journals. But all of that is spread over all of their students.
Regarding the example you introduced: The University of Huddersfield has ~20k students. Its total expenditure is ~120m GBP ($180MM) per year[0]. That's about $9k per student per year. That's less than 1/10th of the $100k expenditure per student quoted in the original article.
[0] http://www.hud.ac.uk/media/universityofhuddersfield/content2...