what i really want in a windows phone that it currently doesn't have. a real gps.

I am a simple person that doesn't use 100% of my phone's functionality but i just like things that are practical. i want my windows phone to be a complete gps receiver that can utilize any mapping system (nokia, garmin, tom tom, etc...). i hate this having to rely on a cellular signal all the time. it would be nice to use my gps with full functionality while talking on my phone. if i visit a national park i would like to use my phone for my gps/camera. i have a goal zero solar pack to recharge the battery so i'm not worried about that outdoors and i can charge while driving in my car obviously. Can anyone explain why this hasn't bee made a reality?