It happens with other stuff as well, the Wii and Xbox 360 were in very short supply initially. Personally though I think Apple can't afford to have a product stockpiled and images get leaked of the design too early, hence the short supply.
Yeah, the short supply is the norm with electronics like this.
I just wish they'd have done (and allowed other stores to do) preorders like for the iPad 1 and like they do for video game consoles etc.
That's just a more hassle free way to get limited stock near launch. I've bought many game consoles on launch days and never waited in line. I just preordered and went to the store hours after opening on launch day when lines were gone and picked up my system.
It's no big deal, but I much prefer that kind of system. But at the same time they offered online orders so I just went that route as I'll never wait in line to buy something. So again, no big deal. Just think pre-orders would have made things more clear cut and less of a hassle for people who don't like lining up to buy things.