With something like C, C++, Lisp, Python or the like, you know that even if some large company abandons it, it probably won’t even make the headlines, since it won’t matter much for the rest of the users of the language – it has a large enough user base that the language will be fine.
But what if the controlling company decided to abandon Dart, Swift, C#, Go, etc.? It would kill the language in an instant. Or if they decided to simply take the language in a new direction more suited to the company but contrary to the wishes of its global user base? I can’t work under those conditions, and neither should anyone else accept to do so.
To clarify: If, say, at least two thirds majority of the development of the language was no longer done by a controlling company (and if the supposedly non-affiliated developers were not also all incidentally employed by the same company), and, in the case of Go, the name was changed, I would probably not have a problem with using any of the aforementioned languages.
P.S.
Rust is a slightly special case, since it’s dominated not by a company, but by the Mozilla Foundation, making it slightly more dependable than an arbitrary company.