As for why production is falling behind demand, I think it’s simply a factor of Apple’s conservatism. Better to have demand outstrip supply than the other way around.
Yes, though I would suggest it’s not just conservatism.
Apple has a lot of faith in their products, so it’s not like they strictly low-ball it. It’s just that what Apple fears more then demand outpacing supply is a roomful of these things in a warehouse for even a few days. In this business, inventory is money lost; Apple prides itself on measuring their inventory in fractions of a day.