[With that said, I think this is actually a really nice article, and well-presented.]
I still see almost no articles in this space: they're all either the (super valuable) jason davies style "here is why they work, it's just linear interpolation!" pages, or very short explanations that give the calculus expression, and then... stop. This in contrast to linear algebra and calculus, which as general maths subjects have an almost countless number of free ebooks, book-sites, college professors putting up slide decks for their entire courses, and researchers making their phd theses and research papers available online.
This is still a niche subject (it's a tiny speck in the Venn diagram of calculus, linear algebra, geometry, and graphics programming), especially as most people don't need to know anything about Bezier curves to _use_ them in things like CSS or Illustrator; you can make them do what you want just by playing with them.
If you need to program with them, though, you have a problem: of course, you can find all the information in this primer if you want to look up 30 different web pages that all cover each section on their own, with disjointed maths notation and level of detail, but that's how you figure out any niche subject in the absence of single page resources like this primer =)
The "computer equivalent of bike-shedding" would be arguing over indentation style[0] and tabs vs. spaces, or over naming conventions[1].
I'm not sure that the thing you're pointing out has a name, actually, but it also shows up in the form of endlessly reimplemented canonical example apps like todo lists as well as the examples you cited.
A related phenomenon - I think - is Zawinski's law of software envelopment[2], as "reading mail" is the kind of feature that meets the same sweet-spot criteria.
[0] https://en.wikipedia.org/wiki/Indentation_style
[1] https://en.wikipedia.org/wiki/Naming_convention_(programming...
[2] http://www.catb.org/~esr/jargon/html/Z/Zawinskis-Law.html