The way I see it, two of the WDW parks are very incomplete adventures: Animal Kingdom and Hollywood Studios. But despite all that, the tourists never realize this because they are going to walt disney WORLD. To any random person who doesn't follow the Disney empire, they would think that they're going to the premiere vacation destination with four parks. Why go to disneyLAND when the WORLD is waiting for us?
Being spoiled by Disneyland, I would never have ever thought of a Disney park being a mere half-day adventure. Never. But with Eisner's handling, parks are opening right off the bat as half day adventures.
Luckily for WDW, Florida never had as big of a critical and local fanbase as Disneyland so I imagine that even if MGM and AK opened as half day parks, there were still enough tourists that wanted to check it out -- so it didn't matter in the long run.
When DCA opened, southern californians were not accustomed to be duped by Disney. We never even imagined a half day Disneyland. The tourists going to Florida however have been being suckered since the early 80s (or some would argue 70s). And too bad for DCA, when you have writers for the Simpsons nearby, game over. The entire world will soon know of the folly that is DCA.
That's the only reason DCA is getting such a huge expansion package. CA is not a tourist destination resort compared to WDW so with DCA sucking so badly, it's certainly not helping matters. Florida's half-day parks however are slow to expand, but they do expand eventually. The tourists will be there no matter what.
It's funny...before, a busy park would mean more expansion, more money going back into the park. In the modern business world, it seems to be about spending less if the money is already there. Spend more only if the first try wasn't successful. I really do wonder what it'd be like if someone in charge actually THOUGHT like Disney did.