Does it really for the average fan? I've been to many, many, many big league sporting events in my life and interacted with literally thousands of other fans, I can't recall ever hearing a single person complain about the league (whichever it was) having too many teams. The average fan is just there to have a good time, but it is their credit cards which actually fund things and not the relatively few super-loyal whose souls cannot go to heaven peacefully unless their team won it all.
If winning it all were the sine qua non of sports, the Cleveland Brown stadium would be completely empty every at home Sunday. The harder truth is that sports is simply a form of entertainment, nothing more and nothing less, and the more fans who are entertained the best it is for the average fans. Expansion entertains more fans; ergo, expansion is good from this perspective as well as the financial ones.