I think you are right overall jrd_x, certainly regarding Mantle and Jeter.
But it is also true that in a way, like Babe Ruth, Jackie Robinson and a few other players before him, Mariano has changed the game itself. He was not the first closer, or even the first modern closer, but I think that teams for years playing the Yankees have had to find a way to get a lead early, possibly leading to mistakes on their part because they took chances, knowing that after the 8th inning if the Yankees had the lead it was probably over.
So in a way he has left a mark up to now that transcends his great numbers and accomplishments. Whether that will be lasting and closers will be seen to have that effect overall on the game when we look back a few decades from now remains to be seen. But to NY opponents the effect has been real enough.
Anyway, for those of us from New York it is shattering news.