When you've been exposed to this kind of life-long influence, it's hard to break out of the mindset. You know John Deere Green, and they've been associated with quality and durability and they belong with you on the farm. They're all but family.
Case, or that weird orange company with the foreign name, on the other hand, are strangers who you don't know if you can trust.
Advertising, no matter how much we say to the contrary, works. And John Deere are old hands at that trade.