Why is there a Midwest?

Why is there a northeast for that matter. The phrase "Why is there a Midwest" was uttered by yours truly one day while driving from Key West back to Miami about 5 years ago? But it still hold true today. Nothing like a couple of days in the sun to re-energize yourself. But I must admit, downfall, sand gets everywhere. Other than that I must say it's all good. So now that I live in NYC I must adjust the phrase to "Why is there a Northeast?" Seriously, New York must have been something around the turn of the previous century, but since the advent of AC, why do people still live there? I must admit, summers are great in cities like Chicago and New York but only because the temperatures mimic places like this? I guess we like what we don't have, or because winter sucks we appreciate summer more. blah blah blah. I guess thats why god invented vacation. . . oh and sunscreen.