That didn't seem to work the same way for say.. mail server software?
Sendmail, postfix and qmail all had BSD-ish licenses, and those three covered quite a majority of all opensource mail serving at the time of BSD-vs-Linux "in the same early years"
Drivers for hardware that is better supported in Linux compared to FreeBSD - 90% of which is graphics - are usually licensed as MIT or BSD, not GPL, even though they are shipped as part of the Linux kernel.
The Linux users gave back (often because they had to) and the BSD users often didn't.