That's rather uninformed statement. There are tons of sub-notebooks that don't limite the angle of the display. Even better, if you go to the macbook air forum and look at the thread about display angle, you'll see that some people have been lucky enough to get MBAs that have displays that can be angled all the way back without any problem - despite the extremely thin base. I played with one of these at the Apple Store and realized how I've been adjusting myself to my Apple computers for several years because of the limited bezel angle.
There is no reason in the world that Apple couldn't have fixed this a long time ago. Instead, they seem to have artificially limited the MBA angle just so that the MBP and MB don't look bad. That's at least my theory....