There is a lot of prior art in the field of PLT, and I did not get a graduate computer science degree, where much of this is taught. In undergrad, the closest classes were very broad overviews of programming paradigms generally.

There's also the difference between being familiar and knowing things in-depth; I was previously aware of the broad strokes of Ada and many of its features, but only at a high level. The point is to deepen this understanding.

(Also, I'm not on the language design team.)