That’s one issue, but another is that they don’t make into successors full replacements. They’ve stuck to WinAppSDK aka WinUI for a while now, but it’s missing such basic elements as a datagrid/tableview which makes it difficult to take seriously as a desktop UI framework.
Also, they didn't even migrate their own internal dialogs with each replacement. You can still uncover dialog styles all the way back to Windows 95-style if you poke around Windows 11 long enough. Whenever they came out with yet another successor, they haphazardly migrated a handful of P1 components and then called it a day.