Actually, the next most logical version is an implement that runs off the PTO drive of a tractor, not drones. One needs to piggyback off existing infrastructure

Actually, the next most logical version is an implement that runs off the PTO drive of a tractor, not drones. One needs to piggyback off existing infrastructure, not replace it. My high school summer job actually was helping with wheat harvest. You can only work when it's hot as you get better prices on the harvest. There were certain kinds of weeds that really clog the combine (usually ragweed, not a huge problem in the early summer, but weird things happen) or cause damage to the cutting head (invasive brush/tree species). We walked the field and pulled anything really bad out. Talk about a way to earn $25/day. You only finished when the equipment was put up for the night.