If it was like the other students I knew who got 4.0s, the time it took them to go from 3.6 to 4.0 was at the expense of other much more enriching opportunities in life. There's hugely diminishing returns in perfecting ones report card, with regard to actual personal educational growth.

I just saw a lot of premed folks that weren't too bright or too dumb that put in a lot of time but would end up close to the grade line and would do anything they could to get up over the top even though they probably deserved a b or a c based on their understanding of the material.

That probably works better at Caltech than at most schools.