Yet by the same token, the greatest tragedy stemming from the loss of Marlon Brando is that he and Alexander Salkind are forever linked to each other in a certain sense. Even after he had completed his work as Jor-el, and then again, when he returned to the world of Alexander and Ilya to take on the role of the Grand Inquisitor, Torquemada, in Christopher Columbus: The Discovery, he was never fully satisfied with his association with the Salkinds. That, I suspect, must have been why, in early April 1992, just before that film ever hit the theatres, he threatened to have his name removed from that film's opening credits --- a threat which ultimately proved empty --- Brando remained rebellious because, frankly, such was his nature to be.
For me personally, Marlon Brando's connections with Team Salkind would have done Christopher Columbus: The Discovery in, even if he had not agreed to be a part of the project. In today's America, you see, the question of who "discovered" the physical land upon which our country now stands is not really a relevant issue for a single motion picture. But truth be told, the Brando/Salkind link will forever be a turning point in the long and winding road that led to Superman: The Movie.
As usual, of course, these are just my opinions. I could be wrong.
Senior Elf-in-Charge, KringleQuest.com, v.5