If you spend time around a wide range of people it becomes clear that there is a baseline intelligence that relates to the speed someone thinks and learns. While extreme intelligence is hard to quantify the lower end of the scale has a dramatic impact on a wide range of activities. People forget that there are about as many people with IQ < 80 as there are people with IQ > 120.

You might be 50% better than your baseline in some areas, but if you can't learn to feed yourself then you are not going to become a dancer.

PS: I think it's best to look at it as leverage, if you need less sleep you can get more done, if you have a higher IQ you can get more done, but if you spend time watching TV then you're getting nothing done.