Would it be that hard to standardize this?

I'm looking forward to the day when gadget designers enable us to use existing technology to better serve the gadgets' use. Take my Palm Tungsten, for example. It comes with a regular ol' AC charger, but it also comes with a doo-hickie that converts the usb cable to a car DC power accessory socket. Meaning it can also use the usb data cable to draw recharging power right from a powered usb port on my computer. My Zen mp3 player can do the same thing.

So why can't I recharge my cell phone via usb (with a cable provided by the manufacturer - free of charge)? Huh? Is that so difficult a concept for them to grasp?