> Of course this wouldn't matter at all if more phones rotated the screens so that the display was upright even if the phone is upside down

Generally I don't want to get my skin oils all over the lenses on my really expensive smart phone.

I think it's about when you put your phone in your pocket, you have to have it top-up while most people put it top-down, shortening the lenght of the cable and pushing against the connector. In that optic top jack is worse, I believe