While I don't dismiss your general point, I will say that anyone who says "how hard can it be" really needs to consider they are falling victim to the Dunning-Kruger Effect. In my experience, that phrase is (typically) a red flag for the latter.
I would also guess (completely un-informedly) that because the simple (and probably correct) answer is very difficult, a lot of companies are trying to avoid it by doing things that are more complicated but also easier. And because they are more complicated, it is not immediately obvious why they won't work....but they won't. Which is resulting in the repeated failures.
Yep, I can see it.