It would, but on a default, non-CM Android-build it would also require you to run StickMount or OTGHelper to mount it somewhere where the apps and OS will be able to use it.
And for that you may or may not need root. And if you're already there, why not just use a custom kernel (with FAT support) while you're at it?
Pretty big leap from root to a custom kernel. But on my Nexus 7 with root and stickmount, the stock kernel does support mounting FAT drives. So support is baked in there.
I guess it comes down to, when you have to jump through enough steps, some of them unauthorised and requiring the user to install additional software, in court you can make a reasonable argument that you are not selling the device with that functionality enabled, therefore you aren't liable for patent infringement.
Is this why a lot of phones stopped having sd card slots? That is probably the single most frustrating regression in tech for me ( I use my phone as an MP3 player).
There's actually a couple other reasons, in addition to the unstated reason of avoiding the FAT patent. First, if you put in a cheap (yet large capacity) SD card in a device, then it will take an extremely long time to index the files on it (such as getting the id3 tags out of the mp3 files). That in turn makes the phone appear to be a low-quality device for a lot of users. Now add onto that the current trend that the user doesn't need to know where files are stored (they aren't stored on devices or file folders, they are associated with specific applications), then you have a usability problem.
