Check the full post for more details. I suspect the demand control is deliberate. E.g., if Apple did make it possible to go with the Pre-style "there's an app for that" instant wireless access point model, why would anyone who owns an iPhone ever consider a wide-area wireless-equipped iPad? Think different... until customer and competitive requirements force you to do otherwise.
According to Engadget, iPhone OS 4.0 may offer tethering on AT&T. Welcome as the ability to use an iPhone as a gateway to the internet will be, this is a mistake. Tethering is a terrible technology and introducing it at this late date is just stupid. There’s a much better way.
Palm had the right idea with the Pre (and apparently Google has the same idea for the Froyo version of Android.) Instead of tethering, turn the handset into a Wi-Fi hotspot, sort of a do-it-yourself MiFi.