According to Christopher Bellito, a Church historian, who was quoted in the article, "It's simple math; it's not a snub. It would be highly unusual to have two cardinals from the same diocese." The article goes on to say that, "Archbishop Dolan appointed in April 2009, will probably not be named a cardinal until Cardinal Egan turns 80 and surrenders his place among the 120 cardinals who serve as papal electors."
It will definitely happen, sometime in the future, as nearly all Archbishops of New York have been named Cardinals, since the late 19th century.
In the meantime, being an Archbishop of New York is a great honor and achievement. And being well liked and keeping a positive attitude and a smile, in the midst of so much pressure, says a lot about the Archbishop. So it seems to me (and a lot of others too), he's on the right track. The "red hat" will come when the time is right and with God's favor.