Coding Horror reviews current thinking about feature/function definition in software and hardware. It's a great review, but he lets consumers (ie. humans, us) off the hook too easily.
The dirty little non-secret of product development is that customers often want features that you believe they won't use, and they don't care about features you believe they'll find essential. Quite often, this is indeed how it turns out. Buyers of complex products are surprisingly poor at figuring out what's important.
Inevitably products are sub-optimal because a percentage of resources has to go towards what sells, as well as to what will produce satisfied customers.
Frustrating, but it's part of the price most of us have to pay. Call it the "judgment tax". Except, that is, Apple. Apple seems to completely disregard what consumers say they want, and instead sells what Apple thinks they really need. And consumers buy it.
How do they do that?!
Update 6/7/07: This was published in the New Yorker 5/28. Must be something in the air.