DJ,
I mean no disrespect, but an isolated incident of an iPhone 4S running iOS 5.1.1 having the same WiFi issue doesn't "prove" that the issue isn't related to iOS 6.x for the rest of us. It is possible that your wife's WiFi in her iPhone simply stopped working and is now broken and can only be resolved with a new phone. It's also possible that there is something inheritably wrong with the WiFi hardware or firmware in many of the iPhones affected by this that came to light in your wife's phone on 5.1.1 and for many of the rest of us when we upgrade to 6, and you are correct that it isn't limited to 6 upgrades.
Either way, it has been proven that the issue is, more than likely, programmatic not hardware, as many have stated. I've seen numerous posts where people have been able to fix there WiFi issue by downgrading firmware on their routers and all kinds of different fixes, but most of those are to a limited few. Either way, the only thing that is 100% for certain is that there is a HUGE number of us that were affected by whatever Apple broke either in production of these devices, firmware coding, or iOS coding and many of us are growing very tired of this issue lingering for so long without a fix.
To be perfectly candid, it's the response by Apple, or lack of, that is causing many of us to consider what we would not have otherwise considered which is moving to a competing Android or Windows Phone. A simple "We acknowledge there is a problem and are working to fix it" would go a long way. It's the same types of challenges that caused so many to abandon Apple in past years which caused them to nearly go bankrupt.
As a business owner myself, I never thought the day would come that I could believe one individual could have such an impact, but I'm seeing a pattern at Apple. Each time Steve Jobs "left" Apple, they took a massive tumble. The problem this time is there is no option to bring him back to save the company. If Apple doesn't get their act together, I truly believe they may be headed on a downward spiral that they will not recover from this time, which would be very unfortunate.