Why do some franchises have higher salaries than other teams?

Answer 1

Generally speaking it is based on the Clubs market. Whether it is a Big market team, such as the Chicago White Sox or the New York Yankees or a small market team such as the Tampa Bay Rays or the Kansas City Royals or something in between. The market is based on the size of the city's population and the teams subsequent fan base.

Big Market cities like Chicago and New York draw lots of fans thus drawing lots of revenue for the team to spend. Whereas, Smaller market clubs draw less and therefore make less money.

A teams relative success of course has something to do with the size of the fan base as well. Therefore a team like the Yankees who have won as many championships as they have also will draw bigger because of it.