I'm also skeptical, but note that "average college graduate = 3x average high schooler" doesn't mean "college triples your vocabulary" because there are two things potentially going on here: the effect of 4 years at college, and the difference between people who graduate college and and people who don't.
Sure. Someone who reads a lot is more likely to go to college, and reading a lot expands vocabulary a lot. (I often mispronounce words because I've never heard them spoken, and had long ago invented my own sound for them.)
Newspaper vocabulary is dumbed down, and TV even more so, because that's their market.
