I believe while other hardware companies are racing to the bottom in prices, Apple is able to extract premium on its hardware and this is really reflected in the gross margin and bottom line.
Could Apple produce a 600$ laptop? Sure. But it is not worth the temporary gains they'd see. A low end line would cannibalize the margins of their other computers. The quality would probably suffer and it would hurt their brand equity. Apple could introduce an economy line of computers and take over way more of the market, probably grow their sales by 25-40% in a year. To me, that is a strong statement... in that they could but they don't.
I think one thing that Apple will have to contend with is the image. As iPhone's and Macbooks become more and more mainstream, the elitism behind it is decreasing. They will need to do some kind of segmentation (and price discrimination). I wouldn't be surprised if they came out with a higher end Pro series priced around 2500.
Full disclose, I do own a few shares of AAPL. So I believe the future is bright for Apple.