It's extremely advanced tech that we don't have, and therefore it's at least futuristic enough for me.
I think it's troublesome to set a specific future official "date" for when Tomorrowland should take place. That's what 60s Tomorrowland was and nothing turned out that way by the 80s.
Maybe what Tomorrowland should really be is what we wish the future to look like and what we can do in the future.
Also...who's to say that no one will watch Downtown Abbey re-runs in the future?