The explanation/excuse I recall seeing, was about space, not thickness. The headphone jack takes up space inside the phone that they’d rather put to other uses, like more battery for example. At least, that seems to make a bit more sense.
Yes it does. I think back then teardown pictures made the rounds where the innards of the two generations where virtually the same, except they added some component where the headphone jack used to be. And as far as smartphone components go, a 3.5 mm jack is pretty big; I'd guess about the volume of a camera module.
I don't know who started the thinness-jack meme, I suspect it was an explanation made up by people other than Apple, since Apple is usually more into omitting things instead of lying.
