Comment by 7bit
Theres a big difference between Enterprise-Level software and games.
Windows earns money mainly in the enterprise sector, so that's where the backwards-compatibility effort is. Not gaming. That's just a side effect.
Anecdotal, you can run 16bit games (swing; 1997) on Windows, only if you patch 2-3 DirectX related files.
The prototypical examples given in the past were for applications like Sim City, hardly bastions of enterprise software.
And with win11, Microsoft stopped shipping 32bit versions of the OS, and since they don't support 16bit mode on 64bit OSes, you actually can't run any 16bit games at all.