Without modern farming most people wouldn't be able to eat. Soil erosion doesn't worry me nearly as much as the constant transformation of farmland into crappy suburban developments, with pretty lawns that contribute nothing to the eco system or food supply.
And no one talks about the overpopulation enabled by the petrochemicals and the Green Revolution.
On geological timescales the rate of erosion is almost instantaneous. We're talking about running out of topsoil in a single lifetime.