

Most often, yes. But there are exceptions. A lot of Ubuntu developers were on Debian in the early days for example. I imagine some still are - there’s a bit of overlap between Debian & Ubuntu developers here and there.
I maintained packages in various BSDs pkgsrc/ports tree, even though I never daily drove any of them, and had them in a virtual machine at best.
A simple, but guilty pleasure of mine is reading HackerNews story titles (and titles only, most of the time), and tooting sarcastic reactions about them. It’s very therapeutic. (And for easier browsing, I made a HN-like website (read-only) for said toots of mine).