I always find it ludicrous that the fans side with these faceless multimillion dollar companies.
Your precious characters aren't going anywhere the families just want some money that is deserved to them - you'd do exactly the same if you're grandfather was Jack Kirby and you weren't getting the money owed to your estate.
It's not that we're siding with faceless multimillion dollar corporations, it's just that the Kirbys have a rather weak claim here.
Sure the Siegels are annoying because they are putting Superman in jeopardy, but they have legitimate claims because they created Superman and then went off to find a publisher for the character.
However, with the Kirbys, you have a cocky lawyer who was successful with Superman and he probably tricked them into thinking that they have a legit case when they clearly don't:
- Jack Kirby's contributions to Spider-Man were completely dropped from the character because Stan Lee hated them. Kirby deserves no credit at all for Spider-Man despite what the Kirbys and Marc Toberoff think.
- The Fantastic Four are very clearly a work for hire creation with Marvel going up to Stan Lee (as a Marvel employee) on the basis to create a superhero team book and he went to Jack Kirby for the art. Or by going by Jack Kirby's account saying that he came up with the concept in the Marvel offices and went to Stan Lee for dialog. The Kirbys have no legitimate case with the Fantastic Four.
- Jack Kirby signed away his future copyright rights with Captain America to Marvel and supported Marvel over Joe Simon when Joe Simon tried to obtain the Captain America copyright under his name. While Shuster and Siegel sold Superman to DC, they didn't give up their potential future copyright claims like Jack Kirby did. It's why they tried to sue DC Comics several times concerning the rights to the characters and why you see the Siegels and Shuster Estate coming out now and they're succeeding. Again, the Kirby's have no legitimate case.
- Jack Kirby's only influence on Iron Man is the design of the original Iron Man armor. Stan Lee came up with the idea, Don Heck designed most of the characters and did most of the art, and Larry Lieber wrote his first appearance. Why should the Kirbys and their lawyer grab Iron Man when the contributions of Iron Man's other credited creators did far more?
- Jack Kirby was assigned to Thor by Stan Lee. It's pretty clear that the Kirbys have no claim for Thor since he was approached by Marvel to work on a specific character.
- I can't find anything on the background of the creation of the Hulk and X-Men so I won't comment on them just yet. But in appearances, they too come off as work for hire creations since even if Jack Kirby wasn't an "official" Marvel employee, he was pretty much treated like one.
But yeah, overall it sounds like Kirbys claim on his Marvel creations is nowhere near as strong as the Siegels and Shuster Estates' claims on Superman. It sounds more like a greedy lawyer who caught wind of the Disney takeover of Marvel and convinced this family that they have a stronger case than they actually do have.