I have a 6.9 inch screen, which is the biggest if not extremely close, and it fits in my pocket just fine. It fits well because it's so thin.
And it would still fit in your pocket even if it was few more millimetre thick. And, it is better to make the pockets bigger by a few millimetres rather than making the phones thicker.
I think mine is stated as 6.7" and pretty thin. I wouldn't say it fits comfortably in all conditions. In some trousers/shorts it either sticks out a bit or digs in my side when I'm sat and bend (to tie a show, etc).