By contrast, the user interface for modular synths is a bunch of knobs and cables. Going to physical knobs on a USB controller and virtual cables on a touchscreen is purely an improvement, and one that vastly expands your expressive capability.
So, guitars are on some axis more expressive than Pd, and less expensive; while analog synths are, in my view, less expressive than Pd, and more expensive. Why would you want to use a less expressive, more expensive instrument that works the same way? Maybe as a conspicuous-consumption status symbol or some kind of meta-level meditation on the nature of modern society, but not to make music.
Your digital keyboard will probably sound a lot better than your upright piano if you get a good set of samples for it and reasonable speakers and headphones. (Well, who knows, maybe you're patching bells and belt grinders into your upright piano. That's harder to do with a digital keyboard...)
Also, I hope you weren't reading any ill will into my "rich people" phrase. I have nothing against rich people. I used to be one. Many of my family and friends are rich people. I might be a rich person again myself someday. I just feel like this article is only relevant to rich people — for those of us for whom spending a few thousand dollars is a significant decision, modular analog synths are silly!