I would not say long shots are exclusive to the West, but it really depends what type of property you are hunting.
ON AVERAGE, eastern properties are smaller. This dictates shorter shots. For may years the properties I hunted on were 40-80 acres...no matter what you did, you could not get a shot over ~300 yards. Currently I hunt on a pretty unique property for the midwest...600 acres...it's open, I've shot deer at 338 yards with a regular muzzleloader and now have a smokeless muzzleloader set up for 500 yards. Yet, in 2 seasons I have yet to shoot past 150 yards with it.
Out in Montana, I've had a mixed bag. Antelope at 200 and 400 yards...mule deer at ~500 yds and a whitetail at 200 yards. Elk hunting I nearly got a decent bull at only 70 yards but could not get a clear shot through the trees...the next day I anchored that same bull at almost 700 yards.
The terrain you are hunting really dictates the range. It's the smaller properties out east which really tend to eliminate the long range shooting. Heck, both states in which I have resided do not allow most centerfire rifles for deer hunting.