I think part of the success was the large Release Version testing - they were getting a lot of hardware feedback prior to release. When XP was released, the drivers weren't included for a lot of hardware (like video cards) which made for many bad installs and hard feelings. It was a catch up game for MS.
Hardware manufacturers are not great at writing new drivers for their legacy products.
Oh, I know that! I still have some forcemeters and other technical tools that use RS232 and parallel port interfaces, and the companies have been out of business for more than 10 years! At least I was able to get communications protocols way back when and roll my own "driver" code that I can integrate in my own programs.
I think it's a testament to the driver model that Microsoft uses that so many hardware devices "just work" when you plug them in. I can plug in a 7 year old printer, or 12 year old camera or 15 year old GPIB PCI card and it just works.