>>26
Yes there is: satisfaction. It's the reason I went into my profession. If I was paid the same as everyone else, I'd still do it in a heartbeat.
Unfortunately, a large number of idiots do it only for the money. This hints at the problem of equal pay: if my vocation didn't make a pile, there would be far fewer of us, yet the demand would remain the same. Do you see the problem here?
Also, an interesting question is who wants to be the janitor or garbage man?