Carrier customers are Apple customers. But remember that the carriers have allocations of launch day stock and Apple simply has a larger amount. Carriers new this and most of them went with the "we'll tell you it will take longer and then we can ship out what we have and underpromise/overdelivery to those that do, without lying to anyone who doesn't". Apple is the main supplier, and they have the right to proportionately allocate launch stock. They've got all the carriers, and the big box stores, their own stores, and online deliveries. And the carriers have stores, and shipped deliveries. Then there is the "pre-orders are sold out but we have to save some for the walk up after you waited in line folks". And Apple isn't the only one saving stock for launch day sales, carriers do it as well. Think how many Apple stores there are, and then think about every wireless store there is. Far more. And people will be waiting in line at those too.
You want it. You want it first. But you have no idea how to manage production - by a partner, shipping, distribution, and sales through multiple methods of upwards of 10 million plus devices on a single weekend. You can't even fathom the logistics. Instead you are just mad that it isn't working out the way you want it to.