> Not all, but the ones that aren't have clear product management of some sort.
That's effectively all of these except maybe ublock.
If you don't have someone trying to sell some portion of your code base, true community efforts not a commercial effort that happens to be OSS, you're probably an infrastructure project.
Blender would be another example. How are they run?
Meanwhile there's thousands of volunteering FOSS projects that are engineers only. Do product & design people not have passion projects? Or they do but are for some reason unable to collaborate with engineers (or vice versa)?
The other problem is the FOSS community itself. See the concurrent post about GIMP [https://news.ycombinator.com/item?id=32624055]. Opinionated devs that either don't see the value of design or having a designer. I know that this isn't true for all projects, but there a bad apples amongst the bigger, more well known projects (GNOME for example) that will spoil it for everyone else. Again, GIMP is a great example of this. As a result, most 'passion projects' lead to designers working on small projects that inspire them, which are rarely software related, ore they look to create something that can provide an income, either as a small second income or as a new business.