By limiting the market, you can do two things: First, you make the device more desirable to those who don't have it. People always want something they can't have. Even if they finally give up, and move on to another product, they're always going to wonder what they're missing with the iPad. If they wonder that, they'll eventually come back around and give it a shot.
But does it increase actual sales? Generally, no.
Secondly, limiting the device somewhat will cause only those who _really, really_ want the device to actually go out and buy it. People who are only looking for a "tablet" device, and don't care whether or not it's the iPad, will ultimately buy the Xoom or something else. Sure, Apple loses their business, but guess what? Those people never cared anyways. What kind of P.R. could Apple possibly stand to gain from blasé users? Very little, indeed. They want their users to be enthusiastic about their device. Waiting for the device creates an attachment to the device before the device is even received. It builds a loyalty that's really hard to break in the long term. Hence the "Apple fan-boy". (How many Microsoft fan-boys do you know?)
Which is why they constantly crow about now many iGadgets they've sold on each call, each keynote, and so on.
No, I think a more likely explanation is that
they want to sell more things, and generate more revenue. It's what their investors expect, it's what pays their salaries, and it's what they constantly brag about.
Thirdly, limiting the device creates a community. Those who got the tablet are seen, in some sense, as outsiders, just like the kid who gets the Walgreen's version of the Wii instead of getting a _real_ one. Sorry, you're not in the club, because you don't have a _real_ iPad, you just have an "alternative". This desire to be in the club will ultimately drive the enthusiasm for the product higher and higher. Not only do you get to own something you don't have right now, but you also get to be in the club. Once you're in the club, you'll see the other members buying the upgrade, and so you'll want it as well.
But does that translate to higher sales? (And thus, higher revenue)
Fourth, unsold iPads are liabilities. Apple has very little to lose by selling fewer, as long as all they produce are sold. Less revenue, sure, but less cost as well.
What they have to lose is all those customers who aren't buying one. By your logic here, Apple should produce as few as possible, to reduce costs. This isn't how retail works: you want to match demand, not be ridiculously short.
Lastly, scarcity drives price. The more scarce an item is, the more people are willing to pay for it. Plain and simple supply and demand.
Then why is one of the main competitive advantages of the iPad its price? Yes, scarcity drives price up in a macroeconomic market. But in this market, one of Apple's goals is to undercut competitors in order to gain a numerical advantage in the market (note the flurry of people surprised at how low-cost the iPad was last year) and to dominate it. You do that through lowering prices (through bulk discount et cetera), not by artificially raising them.
It's genius if you ask me.
It's also bad retail.
Apple has a long-term goal, not simply a short term one.
Yes, and they very well may lose the long-term if they don't attain dominance now. If too many people can't get an iPad and instead go to Android, that hurts their long-term viability.
And in the end, it wouldn't be that hard for Apple to spin up more factories, and for their suppliers to do the same. They just choose not to, in order to maximize the intrigue.
Factory and production management is more complicated than that. Firstly, it isn't just a flippant thing to convert a factory to iPad production; that takes time, money, and training your workers. Furthermore, if you ramp up too many factories, you very quickly reach a point of oversupply, causing that problem instead--and then you have even more factories you have to reconvert and retrain workers for.
There are tons of reasons to limit supply,
Yes, and in the consumer-gadget/electronics market, they're all reasons that are used by companies that end up failing. There are times when shorting supply makes sense, but when your goal is to utterly dominate a market, establish a long-term platform, and to make tons of revenue, there are none. (And that tends to be the goal in consumer-gadget/electronics).
There is no way Apple is intentionally limiting supply (beyond basic factory-management) for the iPad 2. It is absolutely in their best interests to get the thing in the hands of as many people as possible before any competitors get there first. Shorting supply does not accomplish that goal, and it does not look good for investors.