The BSD systems have had 20+ years of divergence. There are areas where they'll borrow from each other when one of the others has a tool that works better than

The BSD systems have had 20+ years of divergence. There are areas where they'll borrow from each other when one of the others has a tool that works better than the status quo, but the kernels are vastly different animals. When a BSD does make a world-breaking change, like pledge(), it owns it, and will patch software itself to handle it, not pester upstream to stop what they were working on to implement their special snowflake code, which is what the systemd developers want to do.