The 5C does not have to sell. It purely has to be the 'other' choice instead of Android etc. being the 'other' choice. It is there to make the deluxe 5S seem a 'bargain', that is all. This makes purchasing the 5S a lot easier for the customer, psychologically.
As for Apple cutting orders due to weak demand, they simply placed a large initial order with their suppliers to get a better price. They probably told them it was going to sell like hot cakes when all along they only needed a modest quantity. They now go back to them and say 'sorry folks we won't be needing so many for the next order' and the suppliers walk away wishing they had charged more per unit with the first order.
Note this article is thin on sources and the angle implied - 'weak demand' is just interpretation.
As for Apple cutting orders due to weak demand, they simply placed a large initial order with their suppliers to get a better price. They probably told them it was going to sell like hot cakes when all along they only needed a modest quantity. They now go back to them and say 'sorry folks we won't be needing so many for the next order' and the suppliers walk away wishing they had charged more per unit with the first order.
Note this article is thin on sources and the angle implied - 'weak demand' is just interpretation.