Laptops cost more than desktops because shaving one inch to stuff something in takes effort. Cramming it all inside a giant lcd screen and the osx operating software is what that 1000 goes towards.
Its so easy any 8 year old can build a pc from scratch and stuff in some giant box. Getting osx to work, completely, on that box is a whole nother matter.
OSX updates can be downloaded without "genuine advantage" phone calls to india and constant monitoring of your computer to make sure their little copy isnt put on another computer(even on shady downloaded copies of osx) .