several iPhone 4S owners I talked to, bought the 64 Gb Model because the 16 and 32 were sold out, and they did not want to wait .........
[thinking the 64 g has a higher margin]
I can believe that. All of the iPhones represent large margins for Apple. Its gross margin this last quarter was incredible (44.7%), driven in part by the leverage high volume in general exerted on fixed costs, but also largely by the high portion of that volume which represented iPhones.
That's part of the earnings success of Apple - it's managed to make its iPhones relatively inexpensive to the end customer while still realizing large margins on them. Much of the cost is hidden from the customer as being paid by the carriers. That 16GB 4GS that the customer is paying $200 for (with contract), the carriers are paying $600 or $650 for. That 64 GB that customers are paying $400 for, the carriers are paying $800 or $850 for. The carriers aren't subsidizing other smartphones to that degree, they don't have to. And the good news for iPhone customers is that those increased costs of business acquisition / maintenance are, effectively, spread out over the entire data customer base of the carriers - that is to say, they don't charge iPhone customers more for monthly service than they charge customers who buy other smartphones (which they don't have to subsidize to as great an extent). In effect, the people that buy other smartphones are subsidizing the people that buy iPhones. That's the marketing power that Apple has built up for itself by providing to customers products that they love, that transform their lives, for which those customers feel there is no substitute.
This is the reason that Apple, while having only single digit percentages of the mobile handset market, accounts for more than half of handset maker profits. I suspect it made more than 60% (perhaps 65%) of handset maker profits in this last quarter. Samsung sells just as many smart phones as Apple (more in the quarter before this last one, though likely a tad less in this last one), but it makes no where near as much money as Apple does - and it is a more diverse company with, e.g., a very strong (and profitable) semiconductor business (in which Apple, ironically, may be one of its biggest customers).