There are a limited number of ways in which we can instigate systemic change (state intervention; social justice movements; legal challenge, etc) so I am not sure why we would expect therapy to have a profound role in cultural shift. Sexual abuse caused me to be disconnected from my body. Sexual abuse is a patriarchal and systemic problem. I cold water swim in order to re-establish my relationship with my body. Should I expect swimming to prompt systemic change?

Therapy is about our internal world and our relatedness to others so the link to systemic change is tangential. Existential therapy might argue that as we shift our understanding of our self we might illicit change in others (we are all connected and change has a ripple effect). In this respect, I agree with Artie that self reflection helps us all move forward.