There was a point a couple of years ago when you could make an argument that phones didn't need cases or screen protectors. Phone makers had been adopting more durable materials, titanium frames were all the rage, and display glass was reaching the point where it could hold up to everyday conditions rather well.
But those days are long gone, and given everything that's happening in the phone industry it's unlikely that they'll be coming back anytime soon. And my recent experience dropping a caseless iPhone 17 Pro Max proves it.