Had BSD not been busy with AT&T lawsuit, all major UNIXes would probably still be around, consuming whatever was produced out of BSD like the networking code and OS IPC improvements over AT&T UNIX.
Instead sponsoring Linux kernel became the plan B, as means to reduce their UNIX development costs.
> Commercial use began when Dell and IBM, followed by Hewlett-Packard, started offering Linux support to escape Microsoft's monopoly in the desktop operating system market
-- https://en.wikipedia.org/wiki/Linux
> 1998: Many major companies such as IBM, Compaq and Oracle announce their support for Linux.
-- https://en.wikipedia.org/wiki/History_of_Linux
Ironically the major contributor to many GNU/Linux critical components, Red-Hat, is now an IBM subsiduary, recouping that investment beyond doing only Aix.
It is no accident that all FOSS OSes that came after Linux, none of them has adopted GPL, as big corporations would rather not be obliged by it.
After all, the GPL forces to contribute back only if you modify and distribute a modified version of the software (the AGPL modified this point, to account for cloud services). A corporation that isn't modifying GPL'd code or isn't redistributing the modified binaries, doesn't incur any additional burden for using a software distributed under the GPL.