If it was simply a matter of targeting the high end, everyone would be doing it.
Everybody is doing it, but their execution is abysmal. They're trying to go toe-to-toe with the leader in those segments without the business and development processes to support it. Apple has singularly focused their entire company on this problem and have the execution nailed. Motorola, Dell, etc. are distracted by the low-margin high volume part of their business and can't focus enough to get it right.
You can't create a high end when there's a thriving low-end and its all commodity. Apple does this by prohibiting clones. There's no competition to pull down prices.
In the PC market Dell would love to go high-end, but they can't because Acer will ship the same machine, with plastic rather than carbon fibre, and sell it at 1/3 the price. Apple doesn't have that worry.
I'm not convinced that to the average buyer there is enough separation there any more to call them separate markets. I know several people who have bought Apple machines recently because they pretty much wanted "a computer" and as far as they were concerned the Apple machines were better enough than the alternatives to justify their higher price. It running OSX was a point of difference but only in the way that people buy eg. a Dyson rather than some other no-brand vacuum cleaner, not like a decision to buy a car instead of a motorbike.
Dell probably would love to have Apple's revenue share, but they don't have Apple's requirements for style so would make a hash of it. Theirs would also end up being plastic instead of carbon fibre.
Yes you can. Lexus, J Crew, AMC tv and many others have proven you can. THe poor and tasteless go for the Crap while the wealthy/farsighted go for the quality/design.
Technology is an echo-chamber. Step outside it and look at what other people have done, then learn from their success.
Only JCrew is in a commodity market. Lexus is really more like Apple. While made by Toyota it generally have very different designs, for example the LS460. AMC TV is clearly not a commodity at all, even less so than Apple.
JCrew is clearly in a commodity market, but they're not exactly upscale. I'd consider them the $800 laptop. Not Walmart/Netbook, but certainly not expensive. And there are expensive clothing manufacturers, but there's a reason why Gap sells hundreds of millions in jeans, while $500 designer jean brands come and go like the wind.
Everybody is doing it, but their execution is abysmal. They're trying to go toe-to-toe with the leader in those segments without the business and development processes to support it. Apple has singularly focused their entire company on this problem and have the execution nailed. Motorola, Dell, etc. are distracted by the low-margin high volume part of their business and can't focus enough to get it right.