No way, I have never had trouble selling my used phone on CL for at least $325+ every year within an hour of posting it.
I have been lucky enough to somehow get an upgrade every year when new iPhones are released even though I have two year contracts.
If for some reason I don't get an upgrade next year, I can sell my phone for around $350 and it will only cost me $300 to upgrade to a new one, only $100 more than a new contract price and I will save all of the fees and junk associated with these programs.
I mean I can see a lot of people being suckered into these plans because of how they are advertised and if you don't calculate it out fully the prices don't really seem that bad to have to pay $30 a month for a phone, but when you want to upgrade after 6 months and you still owe a bunch of money to get the phone half paid off I think people are going to get mad.
I will take the HUGE money savings for the 20min it takes me to sell an old iPhone over these junk plans. Just my .02