That was back when there was "real" UNIX around, as well as a number of clones, including Microsofts own Xenix (maybe they had offloaded that to SCO by then). So UN*X was one way to indicate that it meant UNIX-like OSes.

Turns out SCO bought Xenix in 1987, but Microsoft was just a couple of years removed from being the biggest Unix vendor around at this point.

I guess that's probably Apple now.

Or IBM?

z/OS is officially a Unix

There are an awful lot of iOS and macOS devices out there

macOS is a certified UNIX[0], but iOS isn’t.

[0] https://www.opengroup.org/openbrand/register/

I still think Macs outnumber IBM mainframe and POWER machines by a couple orders of magnitude.

By unit count, no question.

By revenue? Genuinely uncertain.