While I think it's a good fit at DL anyway (fits with the whole "space/Tomorrowland" theme, even though it'll be in a different geographical part of the park), actual physical space might have a lot to do with it. CA is pretty much bounded by roads on all sides; there's literally no where to put it (that I'm aware of!). DL still had room to the north, so there it goes.
(Just looking at a map of the area and while both parks are indeed hemmed in by roadways of some sort, there was more "open space" at DL, whereas CA already goes well up to the existing boundaries).
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