Perhaps we should remember that Linux is a re-implementation of Unix of the times. Back then licensing and other issues stalled access to A&T Unix and Berkeley BSD. Linux provided the Unix/BSD standards for free.

At the time IBM, Sun, HP and many others were charging huge license fees for their versions of Unix which was becoming increasingly fragmented due to the variations between proprietary implementations. Linux cut through all that chaff and delivered Unix, actually POSIX, standards on affordable Intel 386 based systems.