Oh, btw, Windows also runs on millions of ATM machines and on millions of checkout register devices in large and medium and small shops. I don’t see any Linux screens at checkout counters. Windows embedded is also used in many devices not directly known to people, such as consumer electronics, set-top boxes, gaming systems, automobiles, and many other uses. It’s also going to be powering a few billion IoT devices. IoT, remember that? MS is now a leader in IoT tech and software.
But, who’s counting?
Me neither. When I do notice the OS on a kiosk/POS type device it is always Windows. Of course, that's not necessarily a good thing. The only times I notice the OS on such devices is when they are crashing, rebooting, or frozen somewhere in between. ;-)