I think the fact that nobody has followed-up on Walt's vague 45 year old concepts--either within TWDC or otherwise--says at lot about its viability. Urban planning has evolved a great deal over that time and recent history has shown that the public is unwilling to embrace the type of reliance on mass transportation that Walt proposed.
So goes the pessimistic view.
Walt's EPCOT plans were actually quite viable, and are still viable today, and we're finally seeing the possible uses of his ideas in plans like Masdar.
I recall hearing that a lot of people said
Disneyland would be a complete failure and no one would go for it either, but guess what happened.
The problem with Walt's plans is that they were still all being worked out, then he passed away and they didn't have the vision anymore. He had the pull, however to get sponsors and companies working with him, that was going to help fund the project.
I think too many people draw conclusions about the city plan without really taking in the details, or just assuming it would be a disaster. Other than the cost of it, I don't see why.
Currently, there are several residences being used by Disney's CM's, plus all of the hotels, etc. and they're using buses, ferry boats and monorails. So those work ok, but the EPCOT city plan wouldn't? Other than a very smart radial design with better transportation options, what would have been the big disaster?
Frankly I think Walt's EPCOT could have been the failure that tarnished his entire legacy. We all know how much Walt loved futuristic stylings. Financial concerns aside, we have also seen how poorly those futuristic designs hold up. Witness all of the updates that have been necessary to Tomorrowland and the Contemporary over the years.
Frankly I think quite the opposite. I think the idea was just like Disneyland, to consistently update and add new technologies as it became available...an entire separate part of the city was to be devoted to the top companies in America as a test bed.
Walt had all of the right pieces, he had the monorail, he had the peoplemover and he had tested all of them with live tourists!!
If Walt had lived to follow through with his plans, it could have financially destroyed the company. And 40 years later we could be left with an outdated, decaying mass of concrete, steel and plexiglass in the middle of central Florida.
Or we could have had the city design that revolutionized every other urban planning design since then...and wouldn't be worrying about huge gulf oil spills