Knowing your own system and making the right moves. One might argue it was the difference between the New York Yankees of the 1990s and 1980s. Keeping the likes of Derek Jeter, Mariano Rivera, Bernie Williams, Jorge Posada and Andy Pettitte. Trading the likes of Jay Buhner, Doug Drabek, Jose Rijo, Hal Morris, Willie McGee and Fred McGriff. As the current Yankees retool on the fly, they have to get creative and once again that means trades.
Yes, the Yankees have always been blessed with vast resources of cash and those 90s clubs had a solid core of homegrown talent, even beyond the above mentioned players.