“Microsoft was damned lucky that Gary Kildall was too nice of a guy and not savvy enough to fight the whole DOS issue.”
Kindall signed all document of his own free will. In fact, Kindall had full authority to also sell DOS. He didn’t lose that right. Kindall had no legal claims, contrary to your assertion.
Of course Killdal had the right to sell his own software. But good effort at splitting hairs, there. That doesn’t change the fact of where what became PC DOS came from. Sure, Gates and Allen became very wealthy off of that deal. Good for them. But don’t go trying to pass off Gates as being such a great technical innovator with DOS when someone else wrote it and what he sold to IBM was a rip off of CP/M.