I think most people use a case. Not using a case on a glass body $400-1200 device you're going to carry around in your pocket is pretty risky.
Also, the Apple Watch has dramatically cut down on the number of times I have to fish my phone out of my pocket; usage patterns shouldn’t be discounted.
If I had kids using my phone all the time or was constantly juggling it I might feel differently, but I reject the notion that everyone should just put their phone in a case and that be considered the norm.