i think you are overcomplicating my point. when cordless drills came out, people who were used to corded drills, laughed that you would get stuck mid-job without power. nowadays, most cordless drills come with two removable batteries. you charge one while you are using one. when the battery runs out, you just swap them. it takes a few seconds, you get the advantage of cordlessness, and effectively they function all day long under heavy usage.

sure, for military applications, boston dynamics approach is likely more suitable. but for factory, office and home usage, swapping out batteries shouldn't be a significant problem at all.