Surplus can come in the form of a small number of large surpluses, or a large number of small ones. The fisherman is quite capable of being part of the latter example.
He doesn't wish to organize his life around maximizing his output.
The entire point of the story is to get people to consider to what extent that makes sense, and under what circumstances.
If you consider a good life to be precisely how the fisherman already lives, it takes a rather compelling argument (and it make even require compelling force) that he should behave otherwise.
> If you consider a good life to be precisely how the fisherman already lives
That's a pretty big if. I'd start with asking how is dental care in his village. Does the village doctor use anesthesia? Would the anesthesiologist accept fish as a payment, and how many fishes a pain-less root canal treatment costs? Maybe after learning the answers to these questions I'd consider some other definition of a good life.
