Because the Penryns will drop onto the existing Santa Rosa motherboards without a problem, and because HP/Dell/Lenovo/Acer/... will have the 3GHz laptops from day 1?
So you're basing this prediction on what every company besides Apple would do?
Intel will always have something better coming down the pipe, Apple will look foolish if they continually fall behind because they're waiting for something better.
That hasn't stopped them from doing precisely that so far with their current product lines. Come on dude! And all you 'mini-tower' types: examine Apple's history, realize it's blindingly obvious they're never going to behave like a 'normal' computer company, and either accept it or move on.