I would assume you're right about the New York donuts not being temporary; just throwing out a possibility (from someone who's never been blessed enough to even visit that gorgeous park!).
SUPPOSEDLY they were thinking of making a land based around regular cars, or "Carland," until they realized they could make it "Cars Land" after the film. So it could be they just didn't think to change the name and/or didn't think they HAD to change the name.
I actually did like Cars 1 (never saw Cars 2) but I love old towns and stuff. To me, building Radiator Springs (even with a stupid name) has more heart than just trying to make a general "Carland." Though it would've been really neat to see what the Imagineers could've done with it.
(Then again, I still refer to the "Wizarding World of Harry Potter" as "Harry Potter Land." But mostly because it's not a brand new park, just a sub-section of an existing park. And also because it makes me laugh. )