It was a joke, but I found it funny - he explains it with "if there were more, I wouldn't bump into the same people all the time". In other words, his world (th

It was a joke, but I found it funny - he explains it with "if there were more, I wouldn't bump into the same people all the time". In other words, his world (the set of people he normally encounters) is made of at most 5000 people.