It is true that environment (and other non-intrinsic factors) have a huge effect on how much value a person adds to a company (or community, or friendship). I'v

It is true that environment (and other non-intrinsic factors) have a huge effect on how much value a person adds to a company (or community, or friendship). I've definitely experienced this variance personally. That said, if I had my perfect environment, and you had your perfect environment...we would not be equally good at doing particular tasks. For some values of me and you, the difference in effectiveness would be tremendous. We can argue all day if that is due to nature or nurture - but the end result is that some people are just better at doing particular tasks than most other people, by a very wide margin. Also, some people are more consistent in their value add in spite of particular forms of external variance. For a concrete example, there are some people who will very productively stay with a company as it grows from 20 to 2000 people while others will prefer to hop around to stay in smaller companies.