fish has been GPLv2 since well before ridiculousfish took over as the maintainer; changing to GPLv3 is not something we have the appetite or energy for!
Ahh right, tcsh! Thanks for reminding me. I think being so lost at the tcsh prompt is what first prompted me to start learning other shells and ended up with Zsh for a long awhile.
Also, I had no idea the fish dev worked at Apple. I have no hopes of them going with that as a default, but I could certainly see them shipping it as part of the os...
Ironically, the primary developer of fish is an Apple employee. This is probably a significant reason why it's GPLv2 and not v3!