While that's strictly true, there's a wider range of backwards compatibility they're keeping.
See the whole Rust/Cargo problem on Windows. Windows files can't be named con, aux, etc., because the Windows file systems are backwards compatible, generationally, all the way to DOS, which didn't have subfolders initially and which reserved those keywords for special files. Then as DOS added subfolders it still kept that global restriction, then Windows adopted it... and here we are today.
Windows is full of these things, a lot of them coming from DOS and more coming from Win16 or even early Win32.
I know they broke backwards compatibility in the strict sense with Win64, but apart from this not many situations where they did it come to mind. And even for that, they only did it because the overall market for DOS/Win16 was tiny at the point when they did it.
POSIX and its ecosystem is also full of this backwards compatibility baggage (I for example claim that X11 has a lot more outdated backward compatibility legacy than WinAPI - no surprise since it is much older). Just to give a few basic texts about this:
The reason why people tell this all the time with respect to Windows, but much more rarely with respect to POSIX and its ecosystem, is in my opinion that much more programmers have inhaled the latter.
Vista (or was it XP) introduced a new security model that made prior apps that depended on a common install location being writable very interesting... They still kind of worked, but data's actual location was then per-user.
Other than that, most windows software runs as it has for a fairly long time now.
See the whole Rust/Cargo problem on Windows. Windows files can't be named con, aux, etc., because the Windows file systems are backwards compatible, generationally, all the way to DOS, which didn't have subfolders initially and which reserved those keywords for special files. Then as DOS added subfolders it still kept that global restriction, then Windows adopted it... and here we are today.
Windows is full of these things, a lot of them coming from DOS and more coming from Win16 or even early Win32.
I know they broke backwards compatibility in the strict sense with Win64, but apart from this not many situations where they did it come to mind. And even for that, they only did it because the overall market for DOS/Win16 was tiny at the point when they did it.