Baseball has long been about the haves and the have nots. As the only one of big-four sports league to not have a salary cap, Major League Baseball has always seen the biggest disparity between the big-market and small-market organizations.
There's also a tremendous amount of big-market bias among the national media. If you question that, just take a look at the teams who are always platformed during ESPN's Sunday Baseball. It's almost a given that one of the Boston Red Sox, Chicago Cubs, New York Yankees, Los Angeles Dodgers, New York Mets, or Philadelphia Phillies will be part of baseball's premiere primetime slot.