Yep, the copyrighted Socket code legal issue has stalled the BSD world for a considerable time. It's reasonable to conclude many users thought it was a deadend for BSD distros, and when Linux emerged as the most promising thing from all (free as in freedom, open to any contribution, not plagued by a closed governance like GNU hurd) they all emigrated en masses to the effort.

bcantrill has opined that, had Linus gone off to pursue ice sculpture instead, at least one of the BSDs would have figured out a way forward. (Though others suggest that Windows would just have won.) I tend to agree with Bryan though.

https://bitmason.blogspot.com/2020/04/podcast-if-linux-didnt...