Don't these UEFI BIOSes have a quick way to factory reset them. The real sting of viruses is the fact that most people don't want to factory reset their systems due to having so much data on them. However, if I got a virus on my BIOS, I would just factory reset it. Would I have to reoverclock? Yes but its not that much trouble.
You have to consider that while Android sells more than iPhone, it is not by much. I would venture a guess at about 60-40. However, the 60% of android phones is divided among all android makers. Samsung, LG, HTC, Sony, Xiaomi, ZTE, Huawei, Pantech, etc. The 40%, however, is all Apple.