That's true, but it's easier to learn if you keep as many variables unchanged as possible. Once again, Spies job - and that of his crew - is to learn how to be ride (and run) a MotoGP bike. They are preparing (and being prepared) to take over Rossi's spot in the factory team. Giving Spies Rossi's bike, or moving him up into the factory team, merely disrupts that process. Yamaha are thinking long term here, and don't need Spies to perform. After all, they have a man riding for them who has four wins and two second places. Spies has time.