I think that ted is pointing out out a more basic issue with the way Apple handles its pricing and updates.
Doing updates every 6 months mean that there are these large, sharp drops in the price associated with a given level of performance. Meanwhile, the value of a specific computer in a user's hands drops in a smoother, less jerky fashion, because, while it's influenced by the drops in price/performance that come with machine updates, people to some extent anticipate those drops.
Because of this, informed buyers tend to wait until just after new releases to make their purchases: That's the point at which the difference between what the pay for the machine and the value it will have when they receive it will be the lowest. So Apple goes from having fairly low sales on a model to suddenly having a huge number of orders to fulfill, in a short period. People like tedkolb get angry because they feel ripped off, and people like me are frustrated because we have to wait a long time for our lovely new machines to arrive.
If Apple were to arrange for the drops in price/performance to be smaller and come more frequently, their sales of a model would be distributed more evenly across the lifetime of a model. Now, Apple probably can't manage to squeeze out new machines more often -- product development can only be sped up so much by throwing more people at it. But they could start having smaller, more frequent price drops on their machines (say, $50-$100 every month), to smooth out the famine/feast cycle. If they'd been charging $2700 for the 800MHz powerbooks in September, I might have gone ahead and bought then. And while they got more gross revenue out of me now than they would have then, it's not clear that they've gotten more net profit.