The book never came out and said that thing on the wall behind Walt was an early EPCOT Center concept, or that the "community of tomorrrow" he mentioned was the theme park that Disney opened sixteen years after he died, but it implied the heck out of it.
Of course, as the first generation of EPCOT Center geeks grew up and did more reading, we learned all about Walt Disney's actual plan for the Florida property: to build a prototype "city of tomorrow" that would simultaneously function as a tourist attraction and an innovation hub for American industry. The Defunctland YouTube channel recently posted an excellent video that delved into Walt's original concept and ponders whether it would have actually been workable. You should definitely check it out.
The thing that fascinates me most about Walt's E.P.C.O.T. is the inherent hypocrisy of it. The past didn't happen in a vacuum, and Walt Disney wasn't just a wholesome purveyor of family entertainment. The mid-1960s were the height of the Cold War, and Walt was fervently anti-communist. He even testified before the notorious House Un-American Activities Committee about his belief that a strike by employees at his studio for higher pay was actually a nefarious Communist plot to take over his business. Seven years before Disney filmed his E.P.C.O.T. pitch, then-Vice President Richard Nixon and Soviet Premier Nikita Khrushchev had their famous "kitchen debate" where each argued that their country's political/economic system produced the best standard of living.
My point is that Walt Disney didn't just want to build his prototype community to show what a pedestrian-friendly city could look like. E.P.C.O.T. was supposed to be a living repudiation of communism, a gleaming showcase of the American system's superiority. A key tenet of Soviet-style communism was that individual citizens weren't allowed to own property or vote and all decisions were made by unelected Communist Party bureaucrats in bad suits. So naturally, a city built by anti-communist Cold Warrior Walt Disney would be totally different. In his E.P.C.O.T., residents would not be allowed to own property or vote, and all decisions would be made by unelected corporate bureaucrats in better suits. Wait, did I typo just now? No. Amazingly, Walt wanted to demonstrate the superiority of the American system by running his city like a Soviet state! And he never seemed to realize that was what he was doing!
During my childhood in the 1980s, adults would frequently lecture my elementary-school classmates and I on the evils of Soviet Russia. (My 6th grade math teacher was doing it as late as 1990 while the Soviet Union was collapsing. I don't think she watched the news.) The political and economic differences between the Soviet and American systems were a bit over our heads, so what the adults always told us was that in America we had "freedom" and little Russian children did not. This seemed a little hard to grasp at the time because the one thing you do not have as an elementary-school-aged child is freedom. Your existence is basically one long series of adults telling you what to do and yelling at you for doing the wrong thing. But during the Cold War "freedom" was a big selling point for the American system over the Soviet one, which is why it's equal parts disturbing and hilarious that Walt Disney expended so much effort trying to figure out how to legally deprive prospective E.P.C.O.T. residents of it.
The way Walt saw it, the only way to make E.P.C.O.T. the best all-American community of tomorrow it could be was for him to have near-total control over the residents' lives. This would be a place where agents of the city government would have the ability to unlock your doors and come into your house whenever they wanted, only instead of searching for incriminating "evidence" against you they'd swap out your appliances and furniture with new up-to-date ones. It's like if the Stasi were appliance installers. The kind of people Walt imagined as residents of his utopian city were endlessly cheerful and perfectly obedient, with no personal preferences, opinions, or need for privacy. In other words, the ideal denizens of Walt Disney's E.P.C.O.T. were the family from the Carousel of Progress. You know, Audio-Animatronics.
The only workable version of Walt's city was a tourist attraction populated by Animatronics, which is not that far from what the Disney company ended up building. I wonder if Walt would have come to that same conclusion, if he had lived. Would Walt have become like David Nix in the 2015 movie Tomorrowland, unwilling to actually let people actually live in Progress City because it would only mess everything up?
If his city had finally been built it would have been completed in the mid-70s, smack dab in the middle of the Watergate years. Assuming the city had residents, and Walt was able to achieve the level of control he wanted, how would his authoritarian tendencies have played in that era? Would his carefully-crafted "Uncle Walt" persona have survived a more cynical climate? It's a fascinating AU fiction idea for somebody to write.
In the end, the ideal form for Walt Disney's Progress City is probably the model that briefly lived on the second floor of Disneyland's Carousel theater before it was chopped in half and sent to Florida. A lot of Disney fans accept "if you can dream it, you can do it" as a truism, but "if you can dream it and a lot of other people are willing to go along with you, then you can do it" is probably more accurate.