It is not only that the companies pushing those languages have lots of money, it's that they already have lots of users. Often, they publish their language as if it were an "upgrade" from what they were already using, with an even greater chance of success if it is compatible with existing ecosystem.
On the other hand, a language like Nim is starting from scratch. They don't have a specific target audience. There is so much competition in that crowded space that languages which are roughly on par in features and use similar paradigms are fighting for the attention of the geeks who would actually take the time to look, rather than it being bestowed upon them by the people already providing their tools.
Languages are not general purpose in the truest sense. They have their own little ecosystems where they're expected to be used and their proponents are often bubbled in that ecosystem. It's easier to migrate to a new language in your ecosystem than to move to a new ecosystem. Someone just hoping to solve a specific task will pick the tool that has an established history of being practical in that domain and won't take risks with new languages.
Anyway, language choice is often about what's fashionable than what's worthwhile. Did we get stuck with Javascript because of it's superior features or big company backing it? People want to learn whatever is de rigueur, often to improve their job prospects. Does having Nim on your resume give you an edge?
Personally, I've looked at Nim and find it interesting, but not novel enough that I feel I need to use it. What are the killer features that only Nim provides and you feel you can't do without them after using it?