I'd like to ask just how an Intel CPU is "open and scalable" but I think I'll forgo that question.

And having actually lived (and worked) through the Sun, SGI, IBM, and DEC years, I'd have to argue against the idea that they were all "killed" by a little student thing called Linux.

Especially since Linux didn't even exist until 1991.

No, most of the workstations were killed by commoditization. They were specialized machines that were swamped by mass-produced computers with mass-produced processors running mass-produced software. They simply didn't have the resources to compete.