The only reason for that was that the 5 was out of circulation, and the 5S was out of stock. The 5C wont do so good for long.
This is not true! I can walk into any Walmart in my city and get an iphone 5 right now for $29 on contract. The truth is simple... Apple over estimated 5c demand and under estimated 5s demand. It in no way means the 5c isn't selling. It makes up 33 % of all new iphone activations... That's far from a failure. It's sold millions... Not a failure... You wanna see failure to look at sales numbers for Samsung's Galaxy Gear... That's failure.