Good comments here. I'm an old-school hiker who began hiking life with a 1000 mile AT hike in 1974 with a trusty Kelty frame pack loaded with about 50 lbs. Yeah, we knew it was heavy at the time, but that's just what the gear weighed then. You could do that without much trouble because the weight was transferred to the hips (not so much with today's ultralight packs, and I've owned about 6 different ones). Also we used heavy dedicated leather hiking boots which were a good foundation for carrying a lot of weight (don't try this with trail running shoes). Still, we did similar miles (15-25 miles/day) to many modern AT hikers carrying much lighter loads.
I must say, it was a workout but after a few weeks you could get extremely fit, and didn't notice the weight. And if you got in some kind of bind you probably had enough gear to stay warm/dry, moreso than if you are trying to squeek through a hike with minimal light gear; that CAN be a risky proposition out there in the world IMO. I've hiked on the "stupid side of light" and survived, but suffered.