Sure they're complex but tbh they don't need to be. Sorry to bruise your professional ego but you should understand that there's a lot of decisions in bigtech/corporate that equates to 'buy it don't build it, it'll be cheaper, and (secretly) I can show it off on my resume'. And then when you use it, usually it isn't catered for the business' purposes because the tech is meant to cover a large amount of use cases. At that point they move on and the inefficiencies become the norm.

And these require none of the deep math that the lower levels of gamedev stack require. It's tedious, not hard to string all of these web components.