Honestly, no yankee fan, sox fan, mets fan, or LA fan should ever whine about the need for a salary cap. Some people say it should be 110 mil. Why is that? So that the one team that is above it has to be reigned in? Nobody will agree to that kind of thing, especially with the yankees and sox essentially drawing record crowds everywhere they go, and that doesn't happen if the yankees or sox start a season with Cairo, Stern and Stinnett in the starting lineup.
At the same time, the only way it can be instituted is by rolling back all the salaries in the league so that the yankees can get below it immediately and you would essentially be freeing them of some real tankers of contracts. The Yankees play with a huge payroll because it is allowed. The Yankees are going to have their new stadium financed with revenue sharing dollars because it is allowed. The Yankees will also add hotels in the area that they will get cuts of, which is allowed and not included under the revenue sharing agreement. Regardless, the yankees stay above the cap because they can and they make it work. If you forcibly made them stay under a cap, you would have to free them of some bad contracts and they would figure out how to win with the rules as is anyway. You have to give the yankees credit where it is due, have they created a seemingly unfair advantage in comparison to the bottom 3rd of the league, absolutely. Are they smart, hell yeah, they would figure something out to recreate the disadvantage.