To a non-developer, every application they read might as well be a list of buzzwords. They cannot comprehend a word of it. Web stacks offer the opportunity to list more and newer buzzwords. Do I set up an interview with the person who lists "C systems programmer" or with the person who is a "full stack React, Tailwind, Next.js, Node.js, Electron, Docker, Kubernetes, AWS engineer seasoned in Javascript, Typescript, HTML, and CSS"? Well, the latter certainly sounds 10x more impressive. Into the trashbin the systems programmer application goes, they just don't have enough skills for an enterprise of our scale!
A C systems programmer can definitely make a list of buzzwords as well.
Also, let's say team A (10 C app/systems programmers) in a company asks HR to look for a C developer and HR comes back to them with 10 great web developers to be grilled by the engineers of team A - what happens then? Does team A shrug and say "welcome to our C codebase, we shall now rewrite it in tailwind or whatever because you are now here!" - I really don't see how it can play out