No, this is not about “inches” in the context of “size”.
Ron Jeffries in his article on Automated Testing (yeah, a very “exciting” topic for the average person) writes:
“The transition from good enough to excellent occurs at the high end of the range of capability in every endeavor. The fastest runner is fractions of a second faster than the second best, and not very much faster than even the mediocre ones. The world high jump record is about 7.9 feet; mere high school students have cleared 7.15 or more.”