Raymond Chen of Microsoft explained why they go through the effort of coding a lot of special-case compatibility shims for other's misbehaving apps. It's to remove obstacles that prevent customers from upgrading Windows.

(The urls from microsoft.com load very slowly for some reason so may have to use Wayback Machine instead.)

https://devblogs.microsoft.com/oldnewthing/20050824-11/?p=34...

https://devblogs.microsoft.com/oldnewthing/20031224-00/?p=41...

https://web.archive.org/web/20190315130516/https://devblogs....

https://web.archive.org/web/20190315121601/https://devblogs....