To be fair they had to trade Tino, problem was they chose Hitchcock. The biggest issue with the potential dynasty was Chuck spending so much time sucking Scott Boras' balls.
They didn't have to trade Tino they chose to. Tino has said many times that he wasn't looking to break the bank and wanted to stay. He said they never bothered to ask him what it would take and the deal Yankees gave him was way more than he was going to ask the M's for.