I stated that for certain kind of projects it does make sense to use GitHub and similars. My point is mainly about people like me that publish their half-baked code online. I did it because I heard that GitHub was cool; so at least for me it's a fad. I wonder if other devs like me are in a similar position.

> The portfolio/social signalling reason is a tiny part of actual Github/Gitlab use

How so? Are there any numbers about this? Perhaps I write a bot to analyze the distribution of GitHub repositories in terms of stars, forks, #issues, #PRs and can come up with some numbers to back up my hypothesis. I'll publish the code... on my website :)