So for all of the iPhone 4Ses that got the grayed out WiFi problem after upgrading to iOS 7, the only fix that seems to actually work is basically heating up the iPhone up (till about the point it gives a heat warning), then chilling it, and then restarting it. (I've seen this solution in various places, such as this Apple Discussions thread).
But what exactly is happening? Is there still a physically damaged WiFi chip in these devices that the software has been tricked into using? Or is it a weird work around that tricks defective software into working properly?