Jean-Baptiste Quéru, one of the guys responsible for maintaing the Android Open Source Project (AOSP), was recently asked why Google pulled down the factory images for the Nexus 4. This was his response:
“I can't comment on that, sorry.”
What exactly is a factory image? You know how sometimes you do something to your computer that's so terrible that you need to reinstall the operating system? A factory image is basically your Windows 7 install DVD. Most people will never need to resort to loading up a factory image since it's damn near impossible to break a phone, but hardcore Android users will always find a way to tweak the OS to such a degree that it becomes unusable.
So why did Google pull the images? We're going to go out on a limb here and say it was due to Google accidentally leaving 4G LTE support inside the Nexus 4. You may think it was a small oversight, but there are serious legal implications. When companies makes devices with wireless radios, said devices need to get tested and certified by government instituions like the FCC. Google not telling the FCC that the Nexus 4 has 4G LTE is a serious offense.
Does this impact a ton of people? Not really. Everyone who wants a Nexus 4 is stuck waiting for one because of the insane demand. Most of the people who ordered a Nexus 4 care about one thing and one thing only, the low price tag. The few hackers out there who load Android ROMs and fiddle with their devices to the point that they need to be re-flashed with a factory images will always be a highly vocal minority.