Nothing magic about 40 lbs. I was thinking 2 pr of panniers, 2 racks = 10 lbs. Then just thinking 30 lbs of stuff. With some planning a person could probably drop 10 lbs of stuff and 1 rack and pr of panniers. So maybe 25 lbs. Colder weather requires more clothes, isolated areas require more food etc. No stove & pots is possible in more populated areas. where food and water is more available.
I'm sure there are places where you need a weeks food-15 lbs, 5 gal water - 40 lbs, trailer to carry it 15-lbs. But few of us are going to places like that.