Here's an earlier and less cheery version of how a future city might look from Metropolis (1926). Again, we have titanic buildings, sky bridges, aeroplanes flying at a suicidal altitude, and not a blade of grass or any other trace of nature on the non-existent horizon. Meanwhile, far beneath the surface nameless, faceless masses of workers toil without reward or relief from their endless, thankless burdens.
But enough about temping.
If there is one thing that united the artist-prophets, it was a fascination with gigantism. Since the most impressive engineering feats of the early 20th century were bigger and better dams, bridges, canals, and whatnot, it seemed only reasonable that the cities of future ages would look as though they needed a round of thyroid treatments.