I find it an interesting point as it may not exactly be true: A friend of mine works at the docks, loading and unloading ships all day, mostly heavy lifting. To cut a long story short due to his workload he " exercises " every muscle in his body everyday for about 5 days a week, approx 6 hours a day. The guy is very strong.
I find it interesting, in that he breaks every rule of hypertrophy and gets away with it. All his mates at the docks are massive as well.
I also know that the same is true concerning furniture removals. A few guys i know spend all day emptying houses of large pieces of furniture, exercising every muscle every day for hours on end. They are very strong also.
It’s amazing how the human body can adapt.