No doubt! If you were raised anywhere near the NY, PA, Del area, you've most likely been to the Jersey Shore Points. Back in the day the boardwalk was full of pinballs, most having originated from a Philadelphia op, (since those areas are very seasonal and only an hour away). More than likely many of those machines probably ended their commercial lives in other areas or back in PA. 26 years ago I began collecting and flipping pinballs in Southern NJ. An advertisement in the local mailer back then got you phone harassment the entire week with several calls each days from people pleading with you to come take the "Big Ugly Thing" outta here. I guess if they didn't get shipped overseas, they probably didn't go too far.
What hasn't been mentioned along with the large amount of machines is the huge cluster of collectors in the area. With so many pins at the time, probably started the interest and other memories the local pinheads strive to re-create. Only 3 times did I ever ship any games, (twice with OshKosh Ron, now THERE is a name from the past, and once with Dennis Dodel). Never had to, there were just too many collectors in the area willing to make the drive.
Can't forget OshKosh Ron........I remember on one visit, he pulled in to the driveway of my residence with his 18-wheeler at 7AM one morning, (my street was all 12-14K square foot lots with houses), probably woke the entire neighborhood up with that booming country voice of his, then upon leaving, pancaked all 4 of my trashcans filled to the rims. I had to pry them off the street with a crowbar. Those were the days!
I imagine these days, lots of pins, lots of collectors and lots of high-volume hot spots in the north east would be your reasoning.......