Visual art used to be more collaborative that it is now, although some is still going. What we perceive as the work of individual genius was usually a workshop, someone painting backgrounds, another on skies, the boss doing figures and so on.

Obvious examples of mutual art include quilt making but largely speaking, most art was collaborative until the modern era. Even now it's a more a question of attribution than making, Damien Hurst doesn't make his own prints tha'knows.