That's ridiculous that you were down voted. My brother slept on a rock hard bed as a kid and is able to sleep on the floor, without a pillow, all night no problem. The soft bed thing is more of a cultural issue than a biological necessity.

Anyone who has ever been to bootcamp can tell you that it really doesn't matter where you sleep if you're REALLY tired. I would sleep on the ground if they let me. I would fall asleep sitting down, then stand up and fall asleep again. And when I did finally go back to my tent to sleep on my 50 year old army bed in a used sleeping bag, it was the best sleep I ever had.

I've slept on a carpeted floor for decades, zero back issues.

Just one night sleeping on a conventional mattress leaves me with weird back pains and a stiff neck.

Not only are they costly and a PITA to move, mattresses waste a lot of space too.

Traditional Japanese tatami mats are basically the same thing in terms of flatness and hardness, they're not known for having sleep/back troubles.

I absolutely loved sleeping in Japan and Korea. Tatami on heated floors is an absolute pleasure.