First off, my post made clear there is a very big divide between the moral and legal sides of the situation.
Second off, you know I am a lawyer right and have litigated IP cases? Lecturing me on the "legal facts" was certainly a choice.
Third, none of that back history regarding the early deals actually legally matter for the recent court cases. In the late 20th century, copyright law was updated to allow assigned rights to revert to the creators at a certain point because of situations like Siegel and Shuster where creators sold their rights for a pittance before anyone realized what the creation was actually worth. In short, Siegel and Shuster were allowed to tear up their earlier deals, which resulted in the start of the these decades of litigation. It also almost resulted in a very substantial and fair deal in the 90s.
Fourth, morality does matter. In addition to black letter copyright law, there are also intellectual property claims now based on "moral rights". It is a fairness concept that originated in Europe and has spread. Copyright law has been updated several times because of perceived moral unfairness. The whole reason why copyright was extended past an author's death is because the British public were incensed that Dickens' descendants were in the poor house while publishers were printing money from his works.
Last, I completely agree that WB should just settle this now and forever with the estates to prevent more of these claims. The problem is this shysters convinced the estates to tear up the settlements they negotiated in the 90s for snake oil and the estates basically sold their rights to this shyster lawyer, Toberoff, and his buddy, Ari Emanuel. They basically control the estates and their claims now, which makes a meaningful and reasonable settlement with the families practically impossible while they are involved.