Not quite the same, really ....
Apple may not be "selling what people want" because they don't feel like the benefits outweigh the negatives for them at this point in time.
Apple's core focus (currently) is on "media professionals" (by that, I mean anyone from video editors and producers to pro musicians and recording studio engineers, to pro photographers) at the high-end, and the "casual computer user" at the mid to low end.
They feel like they're pretty well equipped to cater to these audiences. (They can help a beginner or casual user, say, migrate all their data from a Windows PC to a new Mac, or provide them with a machine that basically "just works" in more scenarios than a Windows counterpart. EG. Much less virus/spyware concern, the iLife suite making it easy to download from a digital camera or camcorder and work with the results, publish to the web, etc.)
They've been long-established in the media market, at the high end, so they know what to expect from those customers too. Systems like the Mac Pro are largely designed around their needs and past requests.
The "power user" consumer, however, is another story. These people are concerned with getting the highest possible frame-rates in 3D games, or having the best possible benchmark scores on everything from hard disk access to video, while still paying less than "the other guy" for it all. They tend to be "know it alls" who shun ideas like the "Apple geniuses" (because they don't have the depth of knowledge they demand for free, when they come in to ask questions). They demand as many *options* as possible be able to plug into their machine and work properly, rather than accepting the notion that "perhaps, less is more?".
I'm not sure Apple isn't *purposely* avoiding selling the mid-range desktop computers, specifically so they can skip over these people?! They may well figure, "Hey, if you *really* want what we happen to think is a superior operating system and computer experience, you can pony up the money for a Mac Pro and have everything you need ... or just buy an iMac like the rest of our customers do. It's good enough for educational institutions and every casual user and "newbie" we've seen. It's *likely* good enough for you too, if you'd get over your obsession with benchmarks and having to play every single new game that comes out, no matter how insanely high its system requirements are."
I see this whole issue as being the same as with the music industry fighting with downloaded music. It's really a stupid fight because the labels could have made money off this. Everyone knows what the customer wants. The recording industry refused to sell what the market demanded. So the customers bypassed the CD and got their music off the Internet. Had the major labels been there with the product napster and iTunes would never have been created.
No we have Apple refusing to sell what people want. Who knows why but they offer no mainstream desktop machine. So people will bypass Apple. That's stupid. Apple could be taking their money but they let it go to others.