I'm not sure what you're trying to say here, but those "shims" exist. Apps generally do not talk directly to the Executive (kernel). Instead, the OS has protected subsystems that publish APIs.
Apps talk to the subsystem, and the subsystem talks to the Executive (kernel).
Traditionally, Windows apps talk to the Win32 subsystem[1]. This subsystem, as currently designed, is an issue as described in my previous comment.
Yes, I will correct you. Direct Draw games with run dog slow under Windows 8 and up. You can run them at full speed with WineD3D as it has libraries to map both GDI and DDraw to OpenGL.
Ditto with GNU/Linux and old SVGAlib games. It already should have been some a wrapper against SDL2.