Wanda as a theater chain is very powerful. But it's not a successful production company or distributor. Most Hollywood movies don't really want a partner like that. In recent, its parent company Wanda Group are being out of the film business except keeping Legendary. Big debt crisis due to its identity of property developer.
The marketing is fine. Few Hollywood movie stars come to China recently. I'm not sure if it helps. But they really did anything they could.