I would like to toss my two cents in on this one. Where I hunt I can tell you that 4+ year old deer are rarely killed, and that is not because there aren't any. Here people shoot anything and everything, if it is a spike they want to shoot it and show it off to everybody. People just don't get older deer. To my neighbors, a 2 year old is a nice deer and a 3 year old is a giant. They don't kill the 4+ year old deer because they don't hunt for them, they don't put in the work and have the discipline to wait all season for one passing glimpse at an older buck. I went 5 years without killing a deer because I would only shoot a mature buck. In that stretch of time I could have killed dozens of 1 and 2 year olds and probably half a dozen threes. But in all that time I only once had a daylight encounter with a 4 year old deer, and he stayed well out of bow range and never came out during the day again. It may be true that in some places older deer are easier to kill, but where I hunt if you asked my neighbors they would say that they are unkillable. I get 2 and 3 year old bucks on camera during the day all the time, and at all hours of the day. But the two 4+ year old deer I have killed in the last two years made only 3 daylight appearances between them during hunting season over a combined period of nearly 110 days. 3 daylight appearances in 110 days. That is running 4 cameras, and hunting with very low pressure for probably 25 of those days. The numbers don't lie, here if a buck makes 4+ he becomes a ghost.