If I recall correctly, the way they limit how much you can transmit over DOCSIS 3 is by setting modes on each channel and even turning certain channels off. It isn’t an exact science. With fiber, they set a very specific throttle on the Juniper managed switch. The actual connection is 10gbit before the throttle.
I agree that the human body is meant to do much more physical activity than what most of us are required to do in 2018. I believe most depressions and mental disorders are exacerbated by people’s lack of exercise. So, I have some major doubts about completely eliminating the gym.