I believe that it takes a little bit of both here. There are whitetail bucks out there that will never grow huge racks. That's just how it is, the genetics just aren't superior. This has been proven by ranches all around the U.S. Deer are at the point now where they are being genetically engineered (to a degree). Why do you think people "cull" bucks. So much emphasis is placed on killing bucks with inferior genetics to get them out of the heard these days it's become an overwhelming debate in many hunting circles. But then again, bucks don't just get big all because of their genetics. Mature bucks in my neck of the woods get big because they have great genetics, and they have the ability to alude the hunters in the area. Most of the mature bucks shot in my area are smart, and it's tough to kill one because there just aren't that many around. The guys who really know their stuff in our area, generally get one opportunity at a mature deer in a year. ONE opportunity...and that's because the bucks here are tough to hunt. I'm not saying they're not in any of your guys' neck of the woods, don't get me wrong. My conclusion is that big bucks get that way because they've got great genetics, and they've learned how to avoid hunters. My 2 cents.