I think you're right, and perhaps I think the underlying issue uncovered by OP might be: the lack of a single core set of features to achieve a sense of mastery

I think you're right, and perhaps I think the underlying issue uncovered by OP might be: the lack of a single core set of features to achieve a sense of mastery with, that feeling like you've understood an implementation stdlib might have given. (I will admit I've felt profoundly stupid when I go from "how hard could it be to implement std::optional/reference counted pointers/etc., anyway?", to say GNU's implementation of it in libc++.) What the feeling of security that new features giveth, having to work with large idiosyncratic codebases and a wide variety of toolchains taketh.