That does makes sense, but the only time my phone is in my pocket while listening to music is if it's raining. Otherwise, I'm using it while listening or it's on a dock. All putting the port on the bottom does is force me to be more careful about snagging the cable, be mindful of it not getting in front of the screen, and reduce my cable slack length.
I'm kinda the opposite. It's in the way if it's on the top. The cable drapes in front of the screen occasionally and if it doesn't it could snag on anything that gets in between me and the phone. Had a cyclist snag me once. If the port were on the bottom the cord would have been closer to my body and it wouldn't have happened.
I don't carry my phone in my pocket.
Don't tell me you use a holster? "Just put it in your pocket." ;-)
The Office - Dwight's Cell Phone - YouTube