A couple of random thoughts....

1) Better bullets so you can use smaller calibers

2) The average age of hunters going up, who have less tolerance for recoil

3) The trend toward ultralight rifles, which bump the shooter more given the same cartridge

Honestly, maybe it's a regional thing, but in deer and elk camps here mostly the guys still have 270, 30-06, 300WM and 7RM's, with an occasional 25-06, 308, or 338. Been the same for the last 35 years of my hunting.