I wouldn't say that. I think a lot of people moved on to the 5S from the 5, but I think many of us (including myself) have not.
I opt to only pay the subsidy and upgrade every other year. There's lots of tricks to help you get a phone every year like have an extra line on the account so you can buy a subsidized phone every year or just buy the new one full price and then sell your old one.
From what I see though the price of the older model drops when the new model is released - its best to sell it before the new one is available.
The edge program doesn't seem to make sense, you pay full price and you have to trade in the old phone. I think you still do better selling it yourself.