I have to call BS on this. Jeter is a prominent athlete in the Nike stable of endorsements. He doesn't exactly go strolling into Champs to buy his footwear like you and me. He gets his stuff custom made, designed, etc, etc, and probably has 100 versions of every shoe sent to him by Nike. I doubt the guy has bought a pair of sneakers anytime in the last 15 years.
I hate the laundry Jeter wears but as far as personailty goes, he has always been seen as a quiet leader. He's never gotten in trouble off the field. I think your criticisms of him is a bit over the top. My only criticism of the guy is that he's overrated. If he played for Kansas City of Milwaukee the past 15 years, he'd be just another SS.
The Yankees made him an offer that is already higher than what he's worth. They're not worried about him shopping around because no one will match their offer. And any ideas that the Red Sox should spend $50 million on a SS clearly playing the back 9 just to spite the Yankees is silly.