Except that is not how ISP data rates actually work. It is more like the post office tells you it will arrive on X date, and if its late... too bad, "traffic saturation" or "network downtime". But if they have delivery trucks idle and drivers with nothing to deliver "today", your package will just sit in the box for the date is meant to be delivered because you bought your fastest possible speed, not the minimum.

If Internet worked like post you would have the situation I describe, which I'm not even advocating for, I'm just saying ISP QoS and rate limiting is traffic shaping.