Somewhere around that mark (it was 3 when i responded, i believe that is more close to the truth,) maybe more for graphics drivers. Of course, that’s with Microsoft’s legendary commitment to backwards compatibility, more limited scope in which devices Windows targets, and a driver model specifically designed to provide a stable interface.

Linux doesn’t attempt to provide a stable driver model, but based on the fact that many users are stuck on old kernels due to unmaintained drivers, I’m not sure if it would really help that much if it did. Desktop PCs are the place where drivers are most likely to be maintained long term and thats a small part of the Linux install base. The dynamics differ more in the wide range of supported devices.