Good point, but I do concur with you that the 10 X developer legend has always been fortold through out the years and it is now a 'reality' thanks to Microsoft:
Slightly off topic, but with Android going back to version numbers instead of desert names, the next version will be Android 10 .. so we'll have Windows 10, macOS X (10.something) and Android 10. Arguably, Apple has been in the 10 camp longest.
Windows 10 X just sounds like reverse macOS (MacOS X 10.x)
The iPhone X is also still a thing, as well as a lot of Android phones on the bandwagon (and various products like the Tesla Model X, X Windows, X-Files).
I have been irritated by the X-trend for a while, but now it's really getting insane.