As many know, Epcot center was originally going to be an actual city. And it was a reasonably viable plan for a planned city of the future, even if lots of the details themselves wouldn’t remain practical. So what if it got built?
I do think that the general structure of the city’s core was a good design (vehicle traffic completely segregated from foot traffic), but not for Florida. Having an entirely enclosed city center with massive inderground infrastructure (the highway, parking, loading docks) built in a Florida swamp? There are problems there.
Now, it wouldn’t be as convenient for tourism, but what if EPCOT were built somewhere more northerly? Say, the upper midwest. Lots of land, easy to find a place geologically suitable, and an entirely enclosed city center makes sense somewhere where the climate is so cold. Maybe a smaller Disney park could be built (perhaps one that could work as a ski resort in the winter?) nearby. Plus, there’s plenty of heavy industry up there (and plenty more back in the 70s), so those showcase factories would fit right in.