Excellent points there, with a great analogy of a federal government expo
not held in Washington DC.
Even if Disney wanted to spend all the extra money to ship all of the displays and exhibits and pavilions and Walt Disney Archive treasures across the country, in addition to paying for all the executive egos (and middle-management egos as well) to fly out there and be put up in fancy digs, and even if you could convince some Hollywood celebs to also fly out there for at least a day. Even if all that miraculously happened...
You would still be stuck with the logistical nightmare of moving tens of thousands of people per day from WDW property to the Orlando Convention Center, and back again each night.
Even if you hosted some of the smaller exhibits scattered around WDW in the five hotels that have modest conference facilities, you'd still need the big exhibits and the trade show elements in the Orlando Convention Center halls. And spreading it all out miles apart from each other would totally kill the vibe D23 Expo, or any big convention for any industry, wants to try and achieve.
Maybe this little map would help explain why Anaheim is perfect for D23 Expo, and why Disney signed up for a six year contract to use the Anaheim Convention Center for D23 Expo?
Unless D23 Expo is
radically downsized and totally rethought, it's not leaving the Anaheim Resort District, where
everything is within a 15 minute walk of anything else;
Disneyland, Disney California Adventure, Downtown Disney, the largest convention center on the West Coast, dozens of hotels, dozens of restaurants, etc.