My defense of high salaries in sports and show business has always been simple. I believe that anyone should be allowed to make as much money as the market allows, and in turn hopefully they will use those hard-earned riches to employ others, help the less fortunate, and give back to society. In the example of baseball, if the owners of the New York Yankees are making billions, than it's only fair that the players on the field who are the primary attraction should receive a fair fraction of that revenue pie, equal to the talent they have, which spurs the ticket sales, the TV and radio ratings, the merchandise, and so on.
There are many struggling artists out there who work hard following their dreams and live paycheck to paycheck, often having a tough time making ends meet. So many garage bands, so many actors, so many stand up comics will never see a huge payday. When a celebrity becomes a "brand," when their name and face alone is enough to attract an audience to pay money to see them, no matter what the content, then I can defend their high salary, because the success of the project depends almost entirely on them. In such cases, the financial windfall that they earn is justified. The flood of money streaming in is due to their involvement, so a huge chunk of that profit should go to them.
It's not a fair system, however. Often times, the record industry gives naive newbie performers the shaft. On the flip side, does a specific actor deserve the credit for a blockbuster hit instead of the screenwriter or the director? It's sometimes tough to measure what is real value and what is just luck and marketing shenanigans.
What do you think?