The story is attempting to illustrate that fullfilment in life cannot be achieved through sheer accumilation of material goods alone. It seems people nowadays only work toward happiness of that which society directs them to, i.e. build up lots of cash, get a good house, big car, good family but then what? How can someone be fulfilled by the build up of commodities? If we use simple reason they cannot as they will always want something more. Of course, a level of happiness can be achieved through this, I'm not saying it can't. However, for the most part it's false happiness. At some point in our lives everyone has to ask themselves, what do we really want? Is it the materialistic goal of houses, cars and women or is it something more? Unfortunately many people don't come to contemplating this question until it's too late.
Thus, the fisherman is perfectly fulfilled in what he's doing while the businessman's thinking is rooted in trying to comprehend why he dosen't want to achieve the materialistic goal society has set him.