Superman copyrights

I understand the plight of the Siegel and Schuster families in trying to regain the copyrights to the Superman character. But I don't think the two creators were really "ripped off" in the beginning by National Periodicals since I don't know that the company envisioned the character becoming such an icon.

Interesting question, however. If you create something for a company, who owns the copyright? And if you sold the creation to them (even if it's at market value), what obligation does the company have to the creators?

The only sad thing about this battle is that it's not really about whether or not the creations are being used properly or reflected in the literature well, it's about who should profit off of them.