I think we are mostly in agreement. If an industry is standardizing on a language, it's probably a good match for the kind of problems that they solve, i.e. for their problem domain.

Job availability is not just about number of jobs, but also about project quality, companies and personal preference. E.g: I don't have an interest in containers, and most Go jobs involve containers, so this is a minus for Go.

This works in the other direction too. Let's say I want to work for Mozilla, I notice they use mostly C++ & Js, so I decide to invest time brushing up my skills in those areas.