My take on this is in my area Monroe and appanoose county. There are at least twice the number of bucks over 5 as there was in the early 90s when I started hunting in iowa.The differents is at least 5 times the people hunting them. There is also more property's that have high end management than ever so not as evenly distributed as back then.the mature bucks aren't as visible as they were probably due to more serious pressure.
This ^^^^ would describe my thoughts pretty well too, although I have never hunted in these two counties. It is interesting to think of how things have changed over the past 20 years or so. A few of my primary thoughts...
1. Trail cams/surveillence - when someone saw a monster buck 20 years ago it was usually a big surprise to the hunter at the time and often big talk after the hunt with buddies. No one I knew had anything like a trail camera at that time. The only deer you knew about were ones that you had seen in person most likely. Now, when a biggie steps on the scene, most folks refer to him by name and probably have multiple previous year sheds in their basement. What we as hunters know now in a given season is light years ahead of what we knew "back in the day". This allows people to focus on waiting for a big one v. hammering the first antlered buck in their range.
2. Management - I could go many directions here, but while there are still "if it's brown, it's down areas" to be found, it is also incredible to think about the acres now that are being managed at some level. When I first started bow hunting, no one I knew passed ANY racked buck, let alone a "nice one" that was say 120" or so and you would have been considered completely KRAYZEE to pass up something bigger than that yet.
Now it is isn't at all unheard of for someone to pass 150"+ in some situations.
3. Hunter IQ - many hunters today are WAY MORE skilled than what I remember from my early bow hunting career. With zillions of DVD's, seminars, books, websites like this one, on-line shows, etc, a serious hunter can really educate themselves quite well in a pretty short amount of time nowadays. Back in the day, it seemed like it took years for someone to learn the tricks of the trade and only a percentage of guys did develop into likely big buck killers, most were just "deer hunters", far less likely to shoot a real big buck on purpose.
I think there are way more 3 and 4 year olds around than 20 years ago and even some more older deer, but the focus on the big ones is 100x what it was. So in that way, they are harder to get for any one hunter on one particular farm, but since they are much more common, the numbers of "dandies" seems to go higher every year.
Now then, it is also clear to many of us that the late antlerless season has really hurt the overall numbers, which was the goal I guess, but also taken out numerous shed bucks in some areas. So results may vary, depending on the hunting activity and goals in your specific area.