My sense is that that is unnecessarily self-inflicted. Companies' focus on hiring people who already know the language they use is penny wise and pound foolish.

My sense is that that is unnecessarily self-inflicted. Companies' focus on hiring people who already know the language they use is penny wise and pound foolish. Even if a new developer is a complete novice at a language, I would still expect that to be less effort than learning the business domain, getting to know the codebase, and socially integrating oneself with the team.