I Only true to an extent when you compare very high-end computers. Certain common items like the processor are universal, of course, but even components like RAM tend to be much cheaper and less reliable in your typical HP, Gateway, Dell. Motherboards are often custom-designed for the Apple computers and special capabilities are implemented well. What really sets the two apart, though, is the degree to which Apples are carefully designed and tested. You rarely see the same sort of reliability in another system. Buy your family members home-made computers and you'll start to see the difference here.
Apple certainly spends a lot of resources designing and engineering the shells and internal structure, but the vast majority of the internal components in a Macbook or Macbook Pro are not exclusive to Apple and not even premium parts. Not just the CPU, I'm talking about the motherboard, supporting chipsets like the cypress USB Controllers, Realtek Audio, 3rd party bluetooth and WiFi , the SDRAM, the harddrives, the display panel, etc. And I'm not sure what you mean by "special capabilities" considering the Macbook doesn't even have FW400, eSATA, Expresscard, SD/CF card reader, built-in 3G broadband, and other standard items on upscale Dell or Sony laptops.
When you are attempting to compare laptops from the manufacturers, you need to make sure you are comparing models at similar price points. I can't speak for the $500 bargain bin, but decently priced Dell XPS and Precision laptops use top-shelf components like 1920x1200 LED screens (even in 15"), quad-core processors, eSATA, etc.