Bob Kane did the exact same thing to Bill Finger at DC.
Guess the comics were a more cutthroat industry than people realize!
Oh, yes. That is why it was a Musical Chairs industry: Most of them worked for any and all of them at one time or another.
Jack Kirby was, I think, somewhat difficult a personality, but he was entirely correct that Stan Lee denied him the full credit he deserved for his enormous creative input. He did not just draw what Lee said; far from it. No Kirby = No Marvel.
Jack Kirby at Marvel: The Fantastic Four, The Mighty Thor, The Avengers, The Incredible Hulk [first 6-issue run], The Invincible Iron Man, Captain America, The Uncanny X-Men, and on and on. Spider-Man (Steve Ditko) and Daredevil (Wally Wood) were exceptions to his prolific output of new titles.
Fed up with Stan Lee, he went to DC, and produced the whole Darkseid cosmology (which was later somewhat purloined, in my opinion, by Marvel as the Thanos cosmology).
I think Curt Swan (Superman) and many others were underappreciated too. And many of them were very leftist, and some of them wanted to unionize (e.g., Neal Adams).
Bob Kane, to his credit, admitted at an awards ceremony, that he short-changed Bill Finger.
And then look at Jerry Siegel and Joe Shuster: not credited for Superman until the 1970s. Money aside, creation is creation.