I agree with your critiques, but I still don't think it negates the overall picture I see.

When I was a scientist, we were trained to look at the overall body of evidence when trying to assess a claim. Any individual study has flaws, but when we survey the literature as a whole, do we see many studies confirming a finding? Independent studies presumably don't share the same set of flaws (usually), and the more studies demonstrating something, the more likely it is to be true.

And I just haven't heard any counter-evidence. Are job postings increasing or decreasing? What's the change in MAU for Clojurians? Etc.

I looked for job/social media numbers, but it's hard to get those numbers. If you have better data, I'd love to see it.