Didn't it used to be the case that a lot of FreeBSD devs used OSX while OpenBSD devs used OpenBSD and this dogfooding produced better device driver support on OpenBSD?

I heard that somewhere many years ago, but it may be false.

Yes that's absolutely true. And sad. What did FreeBSD do now? They are trying to create an environment to run Linux WiFi drivers. It's so hard to get documentation and support to develop a WiFi driver, less and less people want to do it.