This is still considered reasonable handling. With slightly more bad luck, the 50 pound box falls 4 feet off the top of a stack of boxes. This is a bit abusive, but the shipping industry still feels your packing ought to handle this. It's not surprising that a standard shipping requirement is that the box should be able to take repeated 42 inch drops. They don not have time to see it because of the volume of packages that they handle each day.
Any item carried by truck or parcel carriers simply has to be protected by adequate packing.
Generally, movers handle your goods more carefully than freight companies. A sizeable fraction of the damage done to goods in transit is done by the person receiving the box during the unpacking process. You would think most people would check to be sure all the parts were in view before throwing out a large box or would not pull hard on antique furniture while unpacking it. The solution is to put very detailed instructions for unpacking on most of the boxes shipped. Fragile items need proper handling at all times.