If it is true that no case has gone to trial, that does not mean that there is "no legal recognition of a director's intellectual property." There is. That article is also pretty hazy about what it is suggesting, but the fact that it's harder for directors to prove infringement doesn't mean the concept does not exist. And the settlements tend to suggest the contrary.
The article is interesting in detailing the Urinetown situation which notably involved all of the collaborators joining together, something that highlights that focusing on direction alone is fraught with problems. You say in another post that courts have "rejected" the idea of a director's copyright. Name one. Hint: you won't find one because it does not make legal sense.
If I might respectfully suggest, you seem to be focused on the result rather than the process. Because something is hard does not mean it is impossible: that's the essence of theatre.