I've always wondered about the design flaw of keeping the buttons on the phone below the screen, making it next to impossible to hold the phone with one hand an

I've always wondered about the design flaw of keeping the buttons on the phone below the screen, making it next to impossible to hold the phone with one hand and use the thumb to press the buttons. If you flipped it upside down it was easy to use the thumb though. (actually I still have a button phone, but I figure that everyone reading this thread will have a more modern type of phone..)