Tozzi overthinks it in the article. The kernel succeeded by being in the right place in the right time and then continuously being good enough that there was insufficient reason for change.
Linux, the OS not the kernel, was the first mostly complete Unix available on a college student's budget that would install on hardware the college student mostly already had. Right place, right time. Hurd didn't exist in any usable form, Minix and Solaris were $$ and the *BSD's didn't start to release for a year or two later.
Fast forward four years and when those graduating college students met the Internet bubble, Linux was the server OS they knew. Right place, right time.
Byeond that it was a game of, "don't eff it up." That's where Torvalds' pragmatism came in to play.