Not really, almost everyone I interact with uses a phone case. I have one friend who does not have a case on his iPhone 6, and he's actively trying to break that into a state of disrepair so he can justify upgrading to a new phone.

Can you count how many people you know that do not use a phone case?

I don't know anyone who uses a case. Why bother when you get a new phone every 12-18 months and cases don't stop the screen breaking (unless you get something absurdly chunky)

Anecdotal, but then so is the GP.