This is a pretty interesting article about how native people adapt sleep positions. These sleep positions allow the natural correction of musculoskeletal issues. At one point in my life I slept on the floor with one pillow for 6 years. During this time period I had much less joint pain and problems. I was also much younger and many less sports injuries.
With all the hype on minimalist shoes and paleo/caveman eating, 3rd world pooping squat, I'm surprised sleeping on the floor hasn't had more of a following.
I think there is some validity to the very interesting article posted at the bottom. Should you ditch the bed?
Try it and see if you wake with less body pain! The truth lies in your experience and the consistency of your finding.
Just remember that guys that grow up running barefoot, choose shoes when they are offered. Just because someone goes without, doesn't mean that they choose that way, they are making the best of their situation.