It can also prevent competitors from entering a particular space. I was told as an undergraduate that UNIX was irrelevant because the upcoming Windows NT would be POSIX compliant. It took a _very_ long time before that happened (and for a very flexible version of "compliant"), but the pointy-headed bosses thought that buying Microsoft was the future. And at first glance the upcoming NT _looked_ as if the TCO would be much lower than AIX, HPuX or Solaris.
Then of course Linux took over everywhere except the desktop.
That wasn't even necessarily false. Windows NT on commodity hardware from the likes of Dell arguably did have a lower TCO than proprietary UNIX on proprietary hardware.
But then Linux on that same commodity hardware was lower yet.
Then of course Linux took over everywhere except the desktop.