While this may be true for some places, I am not convinced it is for eastern Montana. The best way reduce age structure of bucks is to hunt them hard when the largest number of buck are on public land. Bucks on pubic are endanger of getting shot at all times, doesn't matter if they are old or young, antlers are big or small.
On private land hunters select for antler size and with a long season during the rut a hunter can afford to be very selective. It is true that as a buck gets older the antlers get bigger, but it is also true that young deer can have big antlers and some deer will die of old age and never grow anything but small antlers. On private the young three year old with 160+ antlers is likely to get shot. The three point that will never be better than 130 will die of old age.
Most of the does are living on private in eastern Montana and during the rut the bucks are right there with the does. A few pages back
@EYJONAS! joked about the old saying " the rut is when the big ones come out". The truth is the big ones were always around, just that before the rut they were up in the hills where most lazy asses didn't want to walk. The biggest migration in eastern Montana is bucks leaving the hills/public for the river or creek bottoms/private to rut with the does. This is made even worse when thousands of doe tags are issued with no restrictions on if they are filled on public or private. Long seasons with lots of pressure tend to push deer to the safety of private and keep them there.
The best way to reduce age class is to tailor the season so that the maximum number bucks are on accessible land during the season and it is likely that this needs to be done on a region or unit sized scale and not a state wide one size fits all season.