If you are a teaching faculty at a university, it is against your own interests to invest time to develop novel teaching materials. The exception might be writing textbooks, which can be monetized, but typically are a net-negative endeavor.
Professionalization of management with its easy over-reliance on the simplification of the quantitative - of "metrics" - along with the scales (size) this allows and manner in which fundamental issues get obscured tends to produce these types of results. This is, of course, well known in business schools and efforts are generally made to ensure graduates are aware of some of the downsides of "the quantitative." Unsurprisingly, over time, there is a kind of "forcing" that tends to drive these systems towards the results like you describe.
It's usually the case that imposition of metrics, optimization, etc. - "mathematical methods" - is quite beneficial at first, but once systems are improved in sensible ways based on insights gained through this, less desirable behavior begins to occur. Multiple factors including basic human psychology factor into this ... which I think is getting beyond the scope of what's reasonable to include in this comment.
https://www.youtube.com/c/ProfGhristMath
This person is amazing.
Add that at research universities, they have to do research.
Also add in that at many schools, way too many students are just there to clock in, clock out and get a piece of paper that says they did it. Way too few are there to actually get an education. This has very real consequences on the moral of the instructors. When your students don't care, it's very hard for you to care. If your students aren't willing to work hard, why are you willing to work hard? Because you're paid so well?
I know plenty of instructors who would love to do things like this, but when are they going too? When are they going to find the time to learn the skills necessary to build an interactive web app? You think everyone outside of comp sci and like disciplines just naturally know how to build these types of apps?
I could go on, but the tl;dr of it is: Educators are over worked, underpaid and don't have enough time in the day.
If big competitive grants and competitive salaries went to people with demonstrated ability like the engineer of this viz, there would be less stem dropouts in colleges and more summer learning! Also, in technical trades like green construction, solar, hvac, building retrofits, data center operations and the like, people would get farther and it would be a more diverse bunch.
Also, according to his home page, Mr. Bycroft earned a BSc in Mathematics and Physics from the University of Canterbury in 2012. It's true that this page isn't the direct result of a professor or a university course, and it's also true that it's not a completely separate thing. It seems clear that his university education had a big role to play in creating this.
Why does YouTube sometimes have better content than professionally produced media? It's a really long tail of creators and educators