The residual value argument is definitely an important point, I agree.
I am not the type of person who lets old gadgets lie around for years. That is, I do not need an ipad 2, ipad 3, and ipad 4 lying around. So I would sell it.
And the resale value of any ios device is far, far, far greater than any android device. The resale value is definitely about perception. The ios or android device didn't really get worse over time (unless you factor in upgradeability issues--android devices rarely get upgrades), but the buying public values the appearance, fit/finish, stability, etc of the ios device much more. People are speaking with their wallets even in the used market.
The resale value is something I have considered as I bought an Android device. I hesitated immediately b/c I knew that a new model would come within 4 months, and what was once cool just 4 months ago is already second-class. As opposed to the general once per year philosophy of Apple. Android, by their rapid release cycles, have hurt themselves. People don't buy when the upgrade cycles are so quick b/c everyone realizes that something new is right around the corner. It irritates buyers. Android once again does not have a real hardware problem. They should fix the software instead of releasing a new model with the fixed software. They really have no clue. Or maybe I don't have a clue b/c when I hear of people saying "yeah I just have to take out my battery about once every 10 days b/c my droid just freezes" and accept it as par for the course, I would never stand for that. But maybe the masses are more forgiving than I am. If my droid froze, I would rather go back to a blackberry.
What Apple has and is (and always will) bet on is the fact that if you build something better, people are going to come up with the money to buy it. Poor people may not be able to afford the "good stuff", but they still want it just as much as everyone else. I'm upset about the ipad mini's pricing, b/c it's an insult to me that Apple thinks that they can pawn off such old technology on us, but people outside this board won't know. I have used the Nexus 7 and it is only tablet that is not crap. The kindle fire is utter crap. If I got it for free, I'd only take it so that I could resell it. So is the nook. The Nexus 7 no doubt has gained ground on the mini. The build quality is not bad at all. And pound for pound, dollar for dollar, the nexus 7 no doubt comes out ahead. But it's the **** ecosystem that Apple has going for it. Android would do well to do whatever it takes to improve the ecosystem. 675,000 apps, yeah, but 670,000 of them are uttery crappery.