I don't think it can be said that they're isolated when the majority of Linux users and (non-system) developers run Ubuntu. And having run various Linux and BSD

I don't think it can be said that they're isolated when the majority of Linux users and (non-system) developers run Ubuntu. And having run various Linux and BSD systems for close to two decades I can say that there is a good reason for that - it's by the far the best distribution out there.