What seems to be ignored is the difference in the muscle itself from more weight fewer reps contra less weight more reps; bigger muscles faster, contra notable endurance gain.

You will always gain size by increasing weight to push the muscle and force it to rebuild as the fibers break down when their potential's limit is approached, but the only way to build enduring muscle fiber is by more reps; by tiring the muscle out entirely to the point it can't do more repetitions. A muscle can be big, bulky, and deliver explosive power, and it can be lean, "tendony", hardy and durable. It is no different to normal stamina build from typical "cardio training" like jogging - every 100 meter extra you add to your trip slowly becomes easier for your entire body - heart, lungs, muscles.

Endurace is also a strength on its own.