However, the computer still needs to be supported by the hardware manufacturer.
Does that mean that companies like HP will be providing updates? If so, why does anyone at Microsoft think this will be a good idea? As anyone who uses Android already knows, there's a good chance that updates will be few and far between. The only way to keep an up-to-date Android system is to use an unofficial distribution of Android, such as CyanogenMod. If you try to create and/or redistribute modified versions of Windows, you'll probably get sued for redicilus sums of money for "copyright infringement".
If this update model doesn't work with Android, which thankfully is full of open-sourced components, why would it be a good idea with Windows, which is 100% proprietary?