Purposely holding back? Or Technologically dumb

I don't understand how my iphone, and most other phones has built in GPS along with a gaggle of other features and technology, and is as small as it is - Yet a giant big honking piece of hardware like the D7000 or other DSLR's doesn't have the room to fit in a GPS unit for photo tagging. Then I look at the add on GPS units for the DSLR's and laugh at their huge size. All this makes me wonder whether the technology is already there for a built in feature and are holding back - or they are simply technologically too dumb to have designed it yet. The GPS chips that goes into phones are about half the size of a thumbnail and about as thin - So I see no real reaon why this hasn't been implemented long ago.

--
Nikon!!!!! Where have you been all my life!!