alt Hacker News> I didn't mean to imply there was something "less" about the talent creating the DOS-based Windows OS. I think it's a marvel of engineering for economy and constraints.
"DOS-based Windows" was not an OS. It was effectively a program which provided a green thread[0] execution model for cooperative processes to execute within and had the reliability one would expect from same.
Windows/386, and later 3.x and 9x, was a virtual machine monitor that could run 16-bit operating systems with 32-bit drivers.
The desktop environment you saw was nothing but the main virtual machine, and inside that was the green thread environment you describe. But the VMM on the outside was pretty solid.