It completely explains why the Epcot monorail is closed today. You just don't like the explanation. It's closed because right now it is simply not needed, and not a priority that will be needed in the short term. If there is no reason to increase costs now, as opposed to sometime in the future, there is no reason to do it.
As to taking a Walt quote out of context, that is just silly. You could given everyone stock in Disney who attends the park. You could given everyone a buy 1 ticket get 3 tickets free deal, they don't. You could hire give every family that enters the park unlimited fast pass (do we see where this is going) no business does that.
As to Universal and WDW, that is like comparing apples and raisins. The attendance figures for Universal Studios vs. the 4 WDW Florida parks is not comparable. Universal sees an opportunity to try and increase market share, and is taking it. WDW is not concerned with market share, nor does it really see Universal as a competitor at the moment. Does that change over the course of the next decade.....I don't know. But given its operating size, its giant place in the market, dedicated fan base, Disney can afford to be more conservative in its approach to openings. If you can point to some downside to not opening the monorail at this time, other than a whiny "but I really wanna ride it" then I would be open to listening. But in face of multiple business reasons why it isn't open, I have yet to see one in favor of it being opened