But Disney isn't "losing" money. Not even close.
They're raking in the dough from everywhere in the world except for the Florida resort. Are you thinking that just having Marvel merch and characters at WDW would dramatically increase revenue? It simply wouldn't, and Disney knows that.
As I've said many times, Disney knows this situation inside and out, and are quite content to sit back and count the Marvel money that's coming in from everywhere but a certain 47 square miles in Florida.
Could you imagine the impact Marvel would have in Japan, Hong Kong, or Shanghai for Disney?