My friend killed his first deer with a .22 long rifle when he was 7. He never hunted deer or elk with anything bigger than a .243. But, he can shoot. I read once that the Eskimos hunt mostly with a .223. The big gun they bring out when hunting polar bear, is a .243. I know that we Americans have magnumitis. Partly because we can, and partly because we want to. I know the rifle I shoot best offhand is my 7mm TCU. It is a joy to shoot, even in a 5 lb. carbine.
As someone else pointed out, bullets today are so much better than 30 years ago. But, picking the right bullet is important. I shot a javelina with a 10" Contender in 7mm TCU with a rifle bullet, and it went right through and the javelina kept going until I put one through the shoulder. Once I switched to a Speer varmit bullet with a huge hollowpoint, they dropped in their tracks. I believe there is a sweet spot between recoil, b.c., and sectional density. For me, it is a 168 gr. 7mm going around 2850 fps. To each his own.
For knocking over deer, I've never shot a centerfire that drops them like a .45 caliber 340 gr. muzzleloader bullet.