The key part to Walt's idea is that it would get better and better. That he felt it would never be finished indicates he expected to keep expanding and improving. A deeper dig down into what has opened and what has closed over the years will show that the recent "expansions" have really been mostly refills to entertainment options that were previously removed. Real growth and expansion has been minimal in the past decade, and there is more monetized "expansion" than atmosphere/experience expansion (ex: Diamond Horseshoe Revew/Goofy's Dancing Jamboree entertainment closed and replaced with another place to buy food | Main Street Cinema replaced by a store to buy expensive Disney art. | Majority of New Fantasyland "expansion" involved building a restaurant with great themeing...but you have to get a reservation and pay for a pricey sit-down meal that's sub-par to enjoy it. The rest of the expansion was replacment of existing attractions with a kiddie coaster. [arguably a better use of the space] In reality, they could have built those new items and kept what already existed as there is plenty of expansion space.)I agree many people are like that, but I've never really been like that - especially when it comes to WDW. I love Walt's quote about how the park will never be "finished", how it can keep getting better and better.
As far as attractions go, I think WDW might be better now than it ever was - and hopefully getting even better with all the new additions (as much as I'm nostalgic about the old EPCOT, the Universe of Energy was a TERRIBLE, outdated attraction and Guardians will (hopefully) just blow it away.)
There is a legitimate argument that the increase in ticket prices is justified by all the new attractions. And if park hours weren't shortened I might agree...
The point is, Walt Disney wasn't one to tear up his old stuff just to make room for new and exciting ideas he had. When he had the idea for Epcot he didn't plan to knock down a portion of MK and shoehorn it in. He envisioned a great expansion in the form of a whole new experience. So, if you are going to quote the man, let's put his words into context so it doesn't look like Walt would be happy with the way DIS CORP is operating his baby.