a lot of community has migrated to GitHub ... because it looks like more "modern" than mailing list. besides, GitHub is the only visible part of community in the perspective of new hands.
No, people don't use GitHub because it looks more modern than a mailing list. They do so because it more closely matches their expectations of how to use computers and software.
Mailing-list likers have not come to grips with this in the last twenty years and I don't expect them to start now, but the dismissive attitude might be preventing you from learning something. "Principal Skinner, it is probably not the children who are wrong."
