No OLED On The iPhone 3GS

We of course monitored the Apple WWDC livestreams.  Thanks to Engadget for doing such a great job (as always).  Apple has added some fun stuff to the iPhone.

Nothing revolutionary - but fun.

One thing we did notice is - no OLED screens on the new iPhones or iPod touches.

We wonder why?

Anyone have any thoughts / suggestions / rumors on this one?

OLED is hot - and is the future - many would say the same about the iPhone 3GS.  Why no love?