As I understand, Linux doesn't have a kernel-to-driver API so "upstreaming" a driver means that you have to maintain it and update every time something in the k

As I understand, Linux doesn't have a kernel-to-driver API so "upstreaming" a driver means that you have to maintain it and update every time something in the kernel changes. Windows driver model is so much better. Windows driver model allows you (in theory) to run drivers written 20 years ago. Linux model doesn't scale because the more drivers the kernel includes, the more work is required to update them when something changes. Also Linux model doesn't allow reusing unmodified drivers by other operating systems. So developers of other OS's have to duplicate the work that already has been done.