The Yankees potentially adding a third jersey could have a lot of pros. First off, more jerseys means more jerseys to sell, which creates more revenue for the team and the league, as well as sporting goods stores and websites that sell them.
But beyond just the monetary benefit, it would diversify the look of the club. The pinstripes are iconic and will never go away, but many other franchises with similar proud heritages have begun to shift toward the uniform revolution of modern sports.
Just take the 16 teams (including the Yankees) that existed before the first two MLB expansion teams (the Angels and Senators/Rangers) joined in 1961. The longevity of these franchises is what draws a lot of people to the game and keeps baseball as America’s pastime.
Despite that history, all of these teams have gone through numerous uniform changes over the years, for better or for worse, depending on your opinion, but almost all of them still have some reference to their historic past.
For example, the Tigers have not changed their home uniform since 1934, yet have had multiple iterations of road and alternate uniforms. That has helped the team both look the part as the years went on, as well as hold on to its history.