My point is that there is a place for technology that is not-mainstream and that there are plenty of (successful) projects build on things that are not mainstream.
In my opinion "mainstream" is not a good factor to select technology on. The factors you mention can be important, but then select based on those not on "mainstream" or not. If you need longevity, pick something based on that, if you need tons of resources, select on that, but not a lot of projects need to live 20 years, and plenty of people prefer well written docs over an abundance in stack overflow answers.
Also mainstream does not mean longevity. Take for example Python 2->3, that was quite stressful to say the least. Plenty of once mainstream languages and technologies are dead or slowly dying, it's very hard to predict.
Continuing on the longevity point, it might be good to note Erlang/BEAM — that Elixer runs on — is older than most languages you mention, still actively used, maintained and developed. So I could very well argue Elixir/Erlang is as safe a bet as any of them.
Lastly I don't think it's true that Elixir is niche enough that this should be a discussion point at all. If you have giant companies running and backing Elixir/Erlang, it's pretty safe to say its battle tested enough and will be around long enough for a lot if not most projects.
Mainstream isn't everything, I wouldn't overestimate it, there are better ways to choose technologies.
In my opinion "mainstream" is not a good factor to select technology on. The factors you mention can be important, but then select based on those not on "mainstream" or not. If you need longevity, pick something based on that, if you need tons of resources, select on that, but not a lot of projects need to live 20 years, and plenty of people prefer well written docs over an abundance in stack overflow answers.
Also mainstream does not mean longevity. Take for example Python 2->3, that was quite stressful to say the least. Plenty of once mainstream languages and technologies are dead or slowly dying, it's very hard to predict.
Continuing on the longevity point, it might be good to note Erlang/BEAM — that Elixer runs on — is older than most languages you mention, still actively used, maintained and developed. So I could very well argue Elixir/Erlang is as safe a bet as any of them.
Lastly I don't think it's true that Elixir is niche enough that this should be a discussion point at all. If you have giant companies running and backing Elixir/Erlang, it's pretty safe to say its battle tested enough and will be around long enough for a lot if not most projects.
Mainstream isn't everything, I wouldn't overestimate it, there are better ways to choose technologies.