A successful programming language is rarely ever something that stands on its own. It’s usually the byproduct of a corporation or some sort of organized committee. It gains relevance through a growing community or standardized through some sort of committee.

To answer the question shortly, programming languages aren’t very profitable. There are so many of them in competition with each other and so few that companies can adopt and base their recruitment around.

Tech startups usually thrive from apps, services, or valuable technologies. Not yet another programming language.