Actually, Apple's cost of materials (which ignores the very relevant costs of marketing, distribution, R&D and all the other stuff that makes the magic happen) is available online ($320 for a 32GB Wi-Fi), and is their profit margin: it's about 35 percent of the total, true cost (this is the profit Apple makes from selling to resellers like Best Buy, Apple dealers et al). The store's profit margin on a $500 iPad is less than $50 last time I looked.
But to your original questions, Lordwarduke and iDavid, I reply thus: have you ever heard of "management"?
The fact of the matter is that you don't actually NEED all that stuff on your iDevice. It is not physically possible, even with unlimited time, to listen to 76GBs of music or play with 20GB of apps (et al) before the battery runs out. So you actually have to put down the thing once in a while to let it charge. Maybe sometimes while it's charging, you could sync it?
Music in particular is childishly simple to manage, even without iTunes Match: make a playlist that swaps out the music each time you sync. Takes no time at all, fresh new tunes every time, frees up a ton of space. Even more so for videos, take off the unwatched ones slap on some new ones, again takes all of a minute.
Yes, never having to sync and being able to carry our ever-expanding collections of stuff on the iPad/iPhone as though it were a magical bag of holding would be wonderful. It would also be nice to have a flying rich wizard for a friend and could give me anything I wanted. Neither one of these things is ever going to happen, however, so instead a modicum of easy management seems to be the best way to let people have the most access to the stuff they own anywhere they go, but the "cost" is a few moments work maybe as much as once a week. Oh the burden of first world problems!