There's nothing really strange about what Microsoft is doing, Apple has been doing it for years. Their OS has been called OS X for how long now?
Actually, the history of Mac OS X naming is interesting.
Originally the name was ”Mac OS X 10.n”, but starting with 10.2 they began using the internal codenames (named after big cats) publicly. So, from 10.2/Jaguar to 10.7/Lion the name was officially “Mac OS X 10.n <Big Cat>”.
Starting with 10.8/Mountain Lion they dropped “Mac” from the title (since the OS was the basis for other, non-Mac devices) and it became “OS X 10.n <Codename>”; with 10.9/Mavericks they ran out of big cats and started using California landmarks (Mavericks, Yosemite, El Capitan, Sierra).
Then, two years ago they dropped the OS X moniker completely. Now they’re referred to as “macOS <California Landmark>”, no OS X or version number. (Of course, the OS still reports a version <10.13.2> to software and the user can see it in the About This Mac dialog.)
Something else to keep in mind is that Windows 10 is trying to implement a rolling release. They don’t want to do point releases (or Service Packs) anymore. They want it to just be a steady stream of updates. In that case, having a version number doesn’t make a lot of sense. Instead, they should simply call it “Windows” and be done with it.
macOS is generally updated yearly (on a tick/tock cycle), with point releases and security patches delivered throughout the year. You’re not forced to upgrade or update, so having version numbers still makes sense.