You mean like never signing an Albert Belle? The case with Manny has more to do with someone who has professed a desire to play for one team. If the Yankmees came up with at least a decent deal, he was going to take it. There comes a point where it just isn't worth the capital for the player.
This is not the same scenario for Harper, if I were the Sox I would go significantly higher for him. However, in my view, I wouldn't for Machado.