Not everything is about those few "specs" you measure (I'd guess CPU, graphics card and memory). This is like judging a house on size and rent price alone -- and thinking that a $200,000 Malibu house is not really worth it compared to a $100,000 Fargo house.
Do you get ALL of the items below for the half price PC laptop?
• More battery life (up to 50% more than most Windows laptops, and topping the best of them by 10-20%)
• Less weight.
• A retina screen, with apps that fully support it (unlike the Windows Hi-DPI situation), and that is shown (on test and measurements) to be the best in laptops for brightness, color rendition etc.
• OS X (and iWork / iLife apps for free as of Mavericks!).
• solid, sturdy alimunium enclosure, machined from a single piece of metal (something that costs), and an industrial design that someone has toiled over, and not a quickly churned out plasticky mess of a case and parts placement.
• Cheap SSD options (compared to buying one yourself or Wintel laptop SSD prices, the pre-configured Mac options are cheaper).
• a multitouch trackpad (of the same quality as Mac's one)?
• NO DVD drive (yes, I'd pay to remove that piece of obsolete crap and have no moving parts on my laptop).
• thunderbolt ports, mag safe adapter, illuminated keyboard, etc etc.
If you don't get all of the above, then you don't really get "the same specs". Just the same memory/CPU/GPU. Especially people who buy laptops but don't seem to value portability (weight/size) and battery life are strange to me...