I may be wrong, but I've never known officials to do it because of the money. Most do it because they love football and it's a fun way to get to watch some games. I understand the issue to not be about the money but to be more about parents/coaches taking the fun out of it for the referees.
That said, I'm not a referee so I could be totally off-base. I've just had a lot of friends who have done it in the past and they all talked about how much fun it is. I've never heard any of them talk about how much money they make.
