There are two separate issues. Contract law. Copyright law.
Hasbro-WotC cannot win the contract law, because the license was and is "open".
Hasbro-WotC cannot win the copyright law, because it is mostly public domain "systems", "concepts", and details from "public domain".
To clarify. 3PPs whose products have the OGL are stuck with it.
But any future products should avoid the OGL at all costs.
The case you cite refers to a photograph. Copyright law normally protects a specific work of photography (as long as it itself is not an image of a 2d image). The angle of perspective is considered an artists creative choice.
I only quickly skimmed thru the case you cited. But it seems to be the case of a business that modified an artists photo but failed to "transform" it enough.
The case doesnt apply. Because a photo actually is copyright protected. It was the actual photo itself that was modified insufficiently.
In other words, if the business took a new photo of the same bridge, there would be no issue.
Here with regard to the SRD, its open domain content lacks copyright protection in the first place. It is unlike a photograph that has copyright protection.
Anyone can use the same "concepts" and "game rules" − but not copy-paste the actual wording of the SRD.
Put it this way. The photographer owns the photo − but doesnt own the bridge that was photographed. If someone else photos the same bridge, it is fine.
Similarly, Hasbro-WotC owns the SRD. It owns the text. But it cannot own its gamerules and concepts.