Only a slight advantage with signing bonuses. There's also a disparity between taxes in different states which Los Angeles gets the bad end of the stick on.
The bottom line is this, Football is a great sport because small town Green Bay, Wisconsin has the same chance of achieving ultimate success as big behemoth cities New York and Los Angeles.
Baseball is a crap sport, because smaller market cities like Pittsburgh, Cincinnati and St Louis have WAY WAY less of a chance of achieving ultimate success going up against big behemoth cities Los Angeles and New York.