The Big Ten conference includes Rutgers in New Jersey, which is a respectable school if you ask people not from New Jersey. It does seem that many students from New Jersey can’t wait to get away from New Jersey (or its state universities) for some reason.
But the answer about why many students stay close to home comes down to cost. Many students find that in-state public universities are among their most affordable choices – it is mainly the few at the top end of the scale who can get the big merit scholarships or admission to the most selective schools with the best need-based financial aid. Travel costs and logistics can also be a consideration.
Those in the northeast may be more prone to wanting to go out of state because (a) the northeast states are smaller, so going out of state is not that big a deal in terms of distance, (b) those in the northeast often consider their in-state public schools to be unattractive for some reason, (c) income and wealth levels are higher in the northeast than in many other parts of the country.