It's because Apple isn't using an OEM PC or even Tech company business model, they are using the business model adopted by luxury brands like Gucci, Louis Vuitton, Channel, Rolex and such. Market a high quality product as a luxury status symbol, then charge obscene prices for the privilege of owning that status symbol. All Apple products, including their Mac Personal Computers, have ridiculous profit margins built in. They then push the concept that to join the cool kids club, you have to buy their latest product. If you don't keep up then you'll be kicked out of that cool kids club.
Basically Apple doesn't compete on price or performance, they compete on perceived exclusivity and brand status. The members of that exclusive group absolutely love to proclaim membership and how great it is, which is why I mock them incessantly. We can talk the merits of tech all day and be fine, but "my logo is better then your logo" is a ridiculous position.