There are several open BSDs.

School-Cotton · 2025-12-16T15:58:44 1765900724

AFAIK there's no evidence to suggest that permissive vs. copyleft license is the reason for the relative lack of success of the BSDs vs. Linux.

pjmlp · 2025-12-17T08:29:32 1765960172

PlayStation and macOS kind of show what happens with upstream.

As did all the UNIXes that used to rule before companies started sponsoring Linux kernel development, and were quite happily taking BSD code into them, alongside UNIX System V original code.