I kind of don't agree with the challenges stated in the video. Because steam download does this properly in estimating the time. The time should just be an estimate of whatever current speed you are on and for other factors like hard disk loading speed the time taken can be averaged. An exact time isn't needed but a rough time would be nice. Steam and old bittorent were good examples. Rendering and other compute heavy tasks should even be more accurate because internet speeds fluctuate way more.