Bought Cortex Command in a Humble sale. It used to have Linux version, and still does, but it's from 2012. Looking into Steam, Linux support isn't even advertised there for Cortex Command. Is Linux version dead?

I believe the Linux builds were done by someone outside of the normal development team - when a build is ready for release, the Linux guy would be sent the source to build the Linux version.

Linux versions weren't done for the latest releases, and I don't think there are any more devs actively working on CC. If you can get in contact with Data, might be able to convince him if he can get someone to churn out the Linux build, but at the moment he's focused on PP.