This question of whether or not the world William Blake represents contains an escape from social and political constraints ultimately involves your personal beliefs and interpretations, and a case can certainly be made on either side of the argument.
In Songs of Innocence and of Experience, William Blake shows how social and political context can shape a person’s life. For example, in “The Chimney Sweeper,” he shows how innocent children are vulnerable to economic exploitation, and in “London,” he highlights the tense political climate and social plight facing the city’s inhabitants.
One might read such works and agree with the idea that there is no escape from social and political constraints. After all, the transition from childhood innocence to harsh adult reality is one that all people experience. Blake depicts this change in a particularly cynical way, and his work can be cited as evidence that no matter how optimistic and pure we are when we are young, we cannot avoid the social and political limitations around us.
On the other hand, one could disagree with Blake’s perspective and argue that this is but one experience of the transition from childhood to adulthood. To make this argument, one could point to the possibilities for life to get better with age and consider examples of people who have broken out of their social and political constraints to live a free adult life.