In what ways might his imagined future seem like a return to the past (his own or humanity's)?
The life at Innisfree describe by the narrator of Yeats' poetry is one which resolutely turns its back on modern urban life and returns to a simpler rural life of the sort that all people had before the advent of modernity.
First, what it lacks are "roadways" and "pavements" -- things built by technology. Thus we see a life away from modern urban life.
Next, the activities are ones that point back to a childhood of Yeats' own or an earlier state of the world. The wattle and daub construction of the cabin is one that was widespread in the neolithic period. Rather than buying food in shops with money earned in an urban job (activities characteristic of sophisticated monetarized societies), the narrator plans to raise his own food (bean rows and beehives), as people would have done in the past.