SJSinNYC: We are not advocating forbidding marrying non close in age. Obviously people will marry whomever the deem to be the right person for them.
HOWEVER, if boys would be set up with girls closer to their own age then in all likelihood they will end up marrying girls close to their own age. In the more yeshivish circles most boys marry one of the first couple of girls that they date. If they would be dating close in age they would more often be marrying close in age, and we wouldn’t have so many hundreds and hundreds of girls with no one to marry.