There is a universe of folks, particularly those in NYC, for whom both are viable options. DS had lots of friends from NYC who could hop on the train and be home quite quickly. Had they gone to NE, the same would have been true.
And there are things at certain schools that simply are not available at a school in the other region. So not all NE kids end up in mid-Atlantic schools (or vice versa) as a result of not having been admitted to a school in their region.