" A very large percentage of land on this planet is given over to agriculture. If we allow landowners to become no more than money-grabbers who see nothing beyond "sound economics," we'll be well stuffed." As in well fed I presume you mean!
With soil erosion the problem first has to be accepted.As I previously stated it is a recent realisation that it is a problem in the UK. Sound economics goes beyond pure financial gain. The means of production must also be maintained and this would include accepting what is presumed to be best practise. No one would argue modern agricultural practise is perfect but inevitably change only comes in response to new knowledge. Sometimes this is to the good, sometimes to the bad. Soil compaction, erosion, using chemicals indiscriminately............... -legislation is slowly taking these factors into account. You may have an argument that change should occur faster in terms of reacting to new knowledge, but it is happening. Chemicals can no longer be used indiscriminately, operators of spray equipment have to be trained, chemicals previously used are banned. Upland areas are subjected to far more controls than was the case even 20 years ago. Agriculture is certainly not the free for all that you endaevour to portray.