I'm leaning towards no
I'm not sure how long the planning takes but I'd think Disney would need to know well in advance, like sometime this year, whether California will allow conventions by that time. If the state sticks the original 4-phase plan, conventions wouldn't be allowed until there's a therapeutic, vaccine, or herd immunity for COVID19. Nobody has much of a clue when that'd be. I doubt Disney would want to risk it and move forward with the planning and then have to cancel if the situation in 2021 doesn't improve (though if that's the case we'll have much much bigger problems to deal with). And given how much grief they're getting over re-opening WDW (grief that the other theme park operators like Uni seem to gotten past unscathed but I digress), I can't see them announcing a move to WDW for the next expo, much as the state of Florida would love it. Actually, due to lack of media goodwill at the moment I can't see them announcing anything on the scale of D23 anytime soon.
The other factor is: while I don't know how much it costs to put on the expo, I'm guessing it isn't cheap, and I don't know if the company's going to be willing to spend the money. Especially with Chapek now making the call.
I'm worried that if they decide to cancel/postpone, they'll use it as a way to quietly end the expo outright. Chapek didn't really seem to be thrilled to be there last year, at least not until he got to announce the dedicated Disney Store shelves in Target, so I doubt he'd miss it.
I do like the idea of a virtual event - Comic Con is doing something like that this year, right? I would think they could at the very least put the non-Hall D23 panels from previous expos on Disney+. Not many would feel dated other than some of the panels that were dedicated to previewing TV/movies/games.
