Seeing how Clojure is actively used at places like Apple, Amazon, Atlassian, and even Walmart where software development isn't even their primary business, I think it's pretty safe to call it mainstream.
Monster lists 68000 positions after a search for 'Java', and 180 for 'Clojure'.
The last Clojure survey has ~2500 people responding. Which is basically the same for several years now. I we assume that 10 times more people are actively using Clojure, then that would be 25000. Still a lot less than the probably 7 million Java programmers and 8 million Python developers. https://www.zdnet.com/article/programming-languages-python-d...
However, there are some other metrics we can look at. For example, if we look at downloads for popular libraries, we can see that Ring's been downloaded 9,058,741 times, and obviously there are repeat downloads for the same users, but even accounting for that it indicates a much bigger user base than you're suggesting. https://clojars.org/ring/ring-core
Other data points would be commercial tooling like Cursive and commercial funding for projects with organizations like Clojurists Together indicates that there is a critical mass of commercial users who are willing to fund projects
https://lambdaisland.com/blog/2020-02-03-open-collective-lam...
https://www.clojuriststogether.org/
Finally, Clojure usage is growing for new projects both in enterprise and government sectors in countries like Finalnd
https://twitter.com/autiomaa/status/1235944730267193345
https://docs.google.com/presentation/d/1nCZ-GmWLcH8Dcz3XJHY0...
This is a very different picture from a tiny isolated community of a few thousand developers that you seem to be painting.
This says nothing about the number of human users.
> This is a very different picture from a tiny isolated community of a few thousand developers that you seem to be painting.
https://opencollective.com/lambda-island#section-contributor...
They have 13 contributors.
It obviously does because people are using these libraries in their projects. As I noted, it's an indirect measure, but it still gives an idea of the usage. And Open Collective was just announced last month, so not sure what point you were trying to make there. Wonder why you didn't mention anything about Clojurists Together, doesn't fit your narrative? https://www.clojuriststogether.org/members/
Obviously it says nothing about the number. If we look at the number of downloads of the current version, it's ~40000. Now many systems may download it multiple times. So the number is not an indicator for a large user community.
> Wonder why you didn't mention anything about Clojurists Together, doesn't fit your narrative? https://www.clojuriststogether.org/members/
It 'fits my narrative' well. Just count the number of the members.
Don't get me wrong, that's all fine and useful in a small community, but to claim a handful of companies and a few hundred people is an indicator of a mainstream popularity is just massive overselling and looks 'silly' (to quote you again, sorry).
Mainstream: large relative and absolute numbers of users.
For example the Porsche Taycan (-> Microsoft) is not a mainstream car, even though Bill Gates has one and Porsche is an incredible profitable company. https://www.economist.com/business/2019/09/12/porsche-is-sma...
I thought being in the top is the definition of 'mainstream': 'most people use it, know it, learn it, ...'.
But Clojure is neither widely known nor widely used. The last Clojure survey was done by just 2500 people.
> You seem to have a personal much more restrictive definition which only includes the top few languages for reasons unstated.
The top ten languages are all two orders of magnitude more used than Clojure. They are mainstream. Literally they have millions of users. That's the definition of mainstream. Mainstream pop: the music most people hear and which dominates the charts. No one would claim that free jazz is mainstream, even though it has some stable fan group.