Tbh the git app or protocol makes it so easy to get up and relocate.. and programmers in general are probably some of the most capable users of relocating that even if it were to happen many of them wouldn't care that much. It's a good portfolio site and decent for collaboration of many projects. Doesn't currently get in the way and provides good or better visibility for projects than gitlab or bitbucket. Till the visibility issue is resolved better by a competitor that offers something significantly better or github makes disastrous decisions then people will be happy at github. Regardless I don't think there would be much drama around moving homes if that day ever comes.