RGB display primaries are only related to the CIE system insofar as people use the CIE system for characterizing and describing them. But it doesn’t constrain the choice of primaries. The primaries are chosen (more or less) to maximize the display gamut under the constraint that there will be 3 of them. They don’t match human cone cells per se (obviously there is some relationship between cone cell responses and maximizing the gamut, but it is not a simple one).
Which I took to be a complaint that XYZ doesn't represent cone response well.
And I responded that that's silly, because (1) XYZ wasn't designed to represent cone responses and (2) the bump is there deliberately to produce a more mathemetically orthogonal basis.
If you go back to all those books you've read over that decade you spent building your expertise, I'm sure you'll find the same info.
So I don't get your criticism. Poster above wanted a set of primaries that corresponds to how the cones react. The closest you can get to that is an RGB space like... sRGB.
Arguing about which design point (phosphor correspondence or cone correspondence) is "real" or "derived" is IMHO meaningless pedantry at this level.
I get that you're trying to be pedantic on this, and that's fine. But the fact that you're complaining about XYZ the way you are shows that... you've sorta missed a few steps. The pedantry goes much deeper, and XYZ is the way it is for some very good reasons.