alt Hacker NewsThat, and design tolerances. A fancy clutch can be light and strong (think ferarri) but farm machines need to work in the dirt/rust and so need larger tolerances. So heavier springs and bigger .... Bigger everything. A slipping clutch in a Ferrari is annoying. A slipping clutch on a tractor means a missed harvest.
Plus mechanical release mechanisms of heavier machinery were often designed in a way that the clutch snaps at a certain point (also in order to reduce wear in the clutch).