Horn: Mitigations are attack surface, too

I don't think there's any claim that Linux could have succeeded without being Free Software. I doubt going semi-free would have worked; a lot of early distribution was done on commercial CD-ROMs, that couldn't have been done with a NC license, and many commercial companies kicked in over the years. We can debate whether the BSD license would have worked; I think GPL is better, but the AT&T lawsuit made the legal status of BSD between 1992 and 1994 confusing, which gave Linux some time to grab market and mind share.

I think it's clear that Linux and the BSDs smoked commercial Unixes, and I think it's clear that's because they were open systems that both individual hackers and various companies could use and distribute. MacOS X is the major commercial Unix left, and they're playing a game that only Apple really successfully plays. The rest is legacy systems and possibly certain huge or specialized systems.