Pardon my ignorance on this subject, but aren't they already kind of doing that vis a vis the Windows 8 on ARM part of their Win 8 development? I am assuming much of the Windows 8 work (at least the Windows 8 on ARM part) is applicable to WP 8. However I am admittedly ignorant of the technical details and may be conflating two entirely difference things - Win 8 and WP 8.
You're conflating two different things. WP8 will be able to take advantage of the tablet drivers and OS work, but that doesn't help the problem with legacy WP7 devices. Those devices won't have the necessary bootloaders and drivers unless somebody (the manufacturers) takes the time and money to write and test them.