I am fairly certain your claim is wrong. Certainly the zooms have gotten better. But the primes have too, especially away from the telephoto end (where they are easier to design).
For example, compare third party lens reviews and MTF charts for the Nikon 50mm 1.8 G to older 50mm lenses. It's just sharper and better performing. Admittedly it distorts a bit more than the AF-D 1.8, but presumably this is a purposeful compromise because we have digital distortion correction now. (And this was designed relatively long ago. The new 50mm for the Z mount is amazing and essentially as good as a Zeiss lens that costs multiples of its price, but it's taking advantage of both increased design power and the shorter flange distance of the new mount, so unfortunately it doesn't really prove the superiority of modern design per se. But it is certainly suggestive.)
Also, design aside, everything else that goes into the construction of lenses is better today, including the coatings, the glass, and the quality control. (You might raise the possibility that the superiority of contemporary prime lenses I noted above is due to these factors and not better computer-aided design. I don't have any hard evidence this objection is wrong but I'd be highly suspicious. In any case, the exact reason why they're better is not really relevant to this thread.)
I haven't checked the wide angles out extensively, but I'm willing to be the difference is even more obvious there. If I recall correctly, the 28mm AF-D Galen Rowell used is way worse than what we have available today. Same for the vintage 35s.
I don't know anything about enlarging lenses, but assuming they are superior to modern macro lenses, I'd bet it comes down more to purposeful compromises in lens design (as you indicated) than a lack of technological progress. I would also be curious to see MTF testing of the enlarging lenses to see how big this purported gap is.
I think it's fairly well known the Epsons can print at 720 dpi, and that this makes a perceptible difference. See for instance this testing by Schewe:
https://www.digitalphotopro.com/technique/photography-workflow/the-right-resolution/.
I think the Canons can print at 600 dpi with the right settings, but this is less well documented.