No, by design Apple only goes after the top X percent of the market. In order to have very large market share Apple would need to offer a computer at each price point. Apple ignores the low margin price points.
Apple will remain forever a boutique reseller by choice. Their problem is that should they ever become truly mainstream they loose the ability to charge premium prices and they become Dell or Compaq.
So how do you explain the cost of the iPhone and its record shattering adoption?
Here is the thing. The middle class in America is disappearing. All these people that are moving into the upper class are wanting and going to want the UPPER CLASS computer. The rest will have crappy PCs. It's sad, but it really is true. People are learning that with a big purchase like a computer, you really do get what you pay for and they want a NICE computer. And now because of the iPod and iPhone they know just how nice Macs really are.
Do you remember when pretty much all fast food meals were $5.00??? Well no anymore lol. They have evolved the market into more upscale type foods and suddenly you now spend $10.00-$15.00 at pretty much any place unless you are eating from a dollar menu. The same thing is happening in the computer industry. And when people get their first make and fall in love, they really don't care that it cost more and they will definitely spend that much more again next time to stay with Apple. Once you go Mac, you never go back