Sure.
I would like this to happen. The Air as the new low-end MacBook, and the MacBook Pro as the high-end. The problem is that the MacBook Air is underpowered and overpriced (simply looking at specs, not at design). It's like the Intel Atom vs. ARM. Once the MacBook Air delivers good enough specs for a MacBook price, then it is time to retire the MacBook.
But the thing is, wouldn't the MacBook be updated too? And the MacBook would perpetually stay ahead of the MacBook Air in terms of performance/$. If Apple was going to replace the MacBook with the MacBook Air, they could:
- Cripple the MacBook so it stays just ahead of the MacBook Air, then one day get rid of the MacBook and bump up the Air's specs.
- Slowly move the MacBook Air down and the MacBook up. In time, the MacBook will merge with the MacBook Pro.
In the end, the MacBook Air and MacBook Pro would be almost as separated as the iMac and Mac Pro. Ultraportable components : Laptop components = Laptop components : Desktop/workstation components
I would like the future of laptops be nothing less than a MacBook Air. But I must advocate heavier and thicker laptops because lighter and thinner ones aren't there yet.