The point of his post is that the market opportunity doesn't exist because the firms professionals are expected to enter take care of that domain-specific training themselves.
For a very long time there has been a "tradition" of sending newly graduated engineers to work on the manufacturing floor, or in product testing for a while so they get background in the business before actually having to design anything. Such a tradition seems to be missing in software development.
Seriously, it looks like there's a market for training professionals to do the vocational side of their job.