Who I have the same questioned this solution

Another thing to consider is that the reason your device isn't fetching a higher price tag isn't because no one want Verizon phones...you have to remember that Apple is just days away from releasing it's newest iPhone and others, like you and I, are flooding the market with 6/6+ and older devices.  We all want $$$ for our device...but unfortunately when the world has a billion (exaggeration) of a particular product that can be had just about anywhere...who wants to pay top dollar for it?  It's simple supply and demand...and right now the supply is higher than the demand for our device. 

If you want to see slightly higher $$$ for your device...keep and older device around and unload your current device a month or 2 before Apple releases its next update.  Once Tim Cook steps on that stage and tells the world about their new device and when it'll be released...it's game over as everyone starts execute plans to dump their current device.