Symbolism, Imagery, Allegory
(Click the symbolism infographic to download.)
Bank Monsters Inc.
You do not want these things hiding out under your bed. Or in your closet. Or anywhere near your farm.
When landowners kick tenant farmers off of the land, they tell them that the banks are hungry, that the bank is part of a hungry monster that cannot be sated. The tractors become:
[...] snub-nosed monsters, raising the dust and sticking their snouts into it, straight down the country, across the country, through fences, through dooryards, in and out of gullies in straight lines. (5.41)
When the tenant farmers try to figure out who is in charge, who they can complain to, the tractor-monsters simply say,
"Fellow was telling me the bank gets orders from the East. The orders were, 'Make the land show profit or we'll close you up." (5.63)
There is no one, specific person to blame, no single person in charge. The banks in the East are hungry for money, but we never get to see the faces of their agents, we never meet a specific landowner or banker. We only know they exist, and that they are turning families out of their homes.