None of that seems to hold them back: they plow into code head first … and … stuff comes out the other end.
Even Slack messages from many of my co-workers are broken fragments of terrible grammar. The syntax is corrupt … let alone the semantics of whatever the hell they're trying to convey.
And I see no correlation between these people, and failure in the corporate world.
Looking at the top quartile of every profession I have been involved in, those people consistently write more and better than their peers.
It depends on what it means by valuable. We may value it, sure, but in his example the poor communication didnt hurt their performance reviews or salaries.
Being a strong writer is incredibly valuable, marketable, and in my experience a pre-requisite for success in the "knowledge economy" (outside of some people that are able to get by on deep technical skills alone).