When did the image of playwright move from that theatrical co-worker to isolated observer and social critic?

The playwright image moved from the role of theatrical co-worker to isolated observer and social critic sometime during the 18th century.

During this time, playwrights began to be seen as more than just entertainers, but also as moral philosophers and commentators on society. This was due in part to the rise of the Enlightenment, which emphasized reason, individualism, and the power of the individual. Playwrights began to use their plays to explore social and political issues, and to challenge traditional values and beliefs.

Additionally, the rise of the professional theater also contributed to the change in the playwright's image. As theaters became more commercialized, playwrights were increasingly forced to cater to the tastes of the audience. This led to a decline in the quality of plays, and a shift in focus from the playwright to the actor. Playwrights became marginalized and isolated, and were no longer seen as important contributors to society.