As someone whose last interaction with Windows was 98 and have been on Mac ever since I also had no idea what a super key was. Also Googled “Windows key” and realized I had seen it before in pictures but never thought about it.

I used some sort of *nix on a VAX terminal in college and ran SUSE on my machine once I realized I hated Windows 98 but all of that is ancient history at this point lol. All of that is to say that it is possible for someone to be peripherally interested in this topic and not be aware of what a super key would be even in context. Maybe someone that uses Windows could pick up on it earlier but I certainly didn’t:)