I disagree. We don't know everything about the 5C, we only know a couple of things and we're assuming all the rest.
There are several posts in this thread alone pointing out that a large number of people will opt for the 5C over the 5S, and I agree completely. But, what each of those 5C sales represents is a missed 5S sale, which is the flagship product as we know, and the product with the most profit for Apple. That's the first problem, I'm sure Apple realises this. The other risk is that the public starts to equate the price of the 5C with the price of the iPhone. I still don't believe that a faster processor (which you can't really say the 5C is slow), a better camera, a fingerprint sensor (whatever), the colour champagne/gold, and a large storage option (128GB) are reasons for the masses to buy the premium model. Apple knows this, they know those features aren't compelling to buy, but they certainly are compelling to forgo to save some significant money on an iPhone. So, the masses start equating the price of the iPhone with the 5C, and in the minds of the public the price of the iPhone is the 5C - who in their right mind would pay more for an iPhone than an iPhone costs? Hard core techies, status conscious people, all or most of whom have more money than sense.
Apple knows all this, much better than we do, and I can't imagine they'd risk that pot of gold the iPhone delivers in profit to them each year, so what I assume is that there is something we don't understand about either the iPhone 5S or the iPhone 5C. At this point the phones are too similar, and that would not be very Apple, or very good business. I think we're in for a surprise or two.