I think your post (and unless I misunderstand, your intent) kind of assumes far far too much context to be helpful. A job interview is a very specific set of conversations, whereas the function of a job at a company can have a very wide array of responsibilities that may or may not be related. If a person has a speech impediment/stutter/something like tourettes syndrome, that problem may only impede one's ability during a high pressure, synchronous conversation. Those symptoms may be totally mitigated by lowered pressure or asynchronous communication. To categorically say that someone that has difficulty communicating in high pressure, synchronous communication situations is unfit for "most jobs" is, to me, a huge miss. Especially now, where remote work is such a big deal, and so many conversations are just-Slack or just-email. If you can have a disagreement over Slack without causing adversarialism or frustration, you're far more valuable to a remote employer than someone that can communicate well over Zoom but poorly in text (I think).
I would say, if a person is able to write clearly and thoughtfully, and is competent at their role, they're very well suited for lots of jobs that aren't sales related. The meritocracy that gets touted so frequently (but is actually never upheld) should reward those that are competent at their advertised skills, right? If you're a really good programmer you should be able to find employment as a programmer, right?