When Dave McKay first used computers, punched paper tape was in vogue, “and he has been programming ever since,” according to his biography page at How-To Geek. It adds that “His use of computers pre-dates the birth of the PC and the public release of Unix.”
Now long-time Slashdot reader sbinning shares McKay’s “short history of UNIX and how Linux got its start,” which ultimately asks if commercial Unix was killed by Linux:
Unix is still out there, running mission-critical systems that are functioning correctly, and operating stably. That’ll continue until the support for the applications, operating systems or hardware platform ceases. If something’s genuinely mission-critical and it’s working, you leave it working. I suspect someone, somewhere, will always be running a commercial UNIX or Unix-like operating system.
But for new installs? There are enough variations of Linux to make the case to go for a commercial Unix very, very difficult.