actually we
have.
go a bit further back than the '50s - during the fur trade, each voyageur was responsible for carrying at least two 90lb standard trade bales in addition to their regular kit - and they didnt have high-tech lightweight hauler frames either. there are Hudson's Bay co. records that recall one voyageur carrying
eight 90lb bales at one time
of course this was alongside maintaining a pace of 55 paddle strokes per minute for 14 hours a day on a low-tech diet of lard and corn.
go even further back, and you have English Longbowmen who drew longbows with up to 190lb draw weights.
how many people do you know today - assisted by modern knowledge, nutrition and supplements - that can come even close to accomplishing that, much less doing it as a
profession every day? i know zero.
the human race has become extremely diminished - i predict in another hundred years most will be morbidly obese slugs that need motorized wheelchairs to get around.
ironically i was just reading a thread where people were discussing different packs for BOB use, and many were criticizing that one pack weighed a pound or two more than the other (but had vastly increased durability/expandability). given that a full two thirds of America is overweight, i wonder how many of those critics are carrying around ten, twenty, or even fifty pounds of excess weight on their bodies that makes the 1-2lbs on the pack seem laughable.