Being able to completely relax mucle in between bouts of activation is just as important for speed and quickness as force production. I've likened being quick to being more similar to dancing, and most real world bouts of quickness are largely based moreso on timing, rhythm, and movement contrasts then they are absolute speed. You should be able to see the parallels with dancing.
A better question IMO is why are a disproportionate number of highly intelligent people are inherently terrible dancers.