Tim Cook admits the iPhone 5C flopped
Some editors on the Verge have repeatedly stated that the 5C will be a 'slow-burn' device, one that might not sell as well as the 5S on launch week, but be in steady demand over the course of a year. As it turns out, Apple competely overestimated demand for the 5C, and sales figures seem to never have met the projected volumes, even after the Christmas period.
This is evidence enough to conclude that the 5C was a failure in the market, but the reasons why that happened are complex. IMO the two decisive factors were the pricing (too close to the 5S) and lack of carrier endorsement. Looking at the home screens of Verizon, AT&T, T-Mobile and even Vodafone UK, the 5C is nowhere to be found. There are some Samsungs, obviously, some other droids, perhaps a 5S somewehre, but no 5C. Verizon even advertises the 4S for 0.99$ on contract on its home screen!
Truth is, carriers do not seem to like 'slow-burn' devices, because they are not flashy enough to market them. For a complany like Apple that has to stir up a lot of hype to sell 'expensive' handsets, there is only the option of selling 'This Year's Greatest' at $199 and 'Ye Olde One' for free. The 'kinda-great but not the greatest' doesn't appeal to virtually anyone. I guess selling iPhones to carriers is something completely different that selling to iPods to consumers.