In my opinion, land themes are a bit more flexible than that. New Orleans Square, for instance, takes place in the 19th century, but the attraction, Pirates of the Caribbean takes place well before that. It still hits all the major aspects of fitting into the theme without a rigid adherence to the time setting.
Likewise, Tower of Terror hits a lot of the major themes of that area of the park: it's a representation of the golden age of Hollywood and it deals with production in a way that puts the audience in the center of it all. Yes, there are some anachronisms, but who's to say when they retheme that area there couldn't be an implied element of time travel walking down Sunset Blvd. (just as there is in the early parts of PotC). Near the current backlot section the street could look brand new and freshly paved, while getting progressively more weathered and degraded as you approach the hotel.
There's no reason to abandon the theme of an entire area because one popular attraction doesn't fit perfectly.