David never really answers the question, but it in an interesting question nonetheless. I have a pet theory that is directly related to a previous statement made by John Gruber:

[...] the way you get to be a billion dollar company is by having a nose for opportunities. $100 million is $100 million.

In the past, Apple has avoided making *unnecessary* accessories. Today, they are taking the opportunity to expand their horizons and make a few extra dollars. Why? Because they can.