Just wanted to let you know that Toyota finally fixed my problem with the hitch. They removed the 2" Toyota hitch that the dealer/factory installed and replaced it with a 1 1/4" hitch. The two hitches are exactly identical (both are DPS / dual port Reese hitches), except the new hitch sits about 2-3" higher and has a lighter towing capacity. Since I only have a 2000 lb boat it is not a problem.
The hitch has not hit the ground since they replaced it, and I have even towed my boat (which I never dared to do before).
I had to call the factory and talk to the factory "regional distributor" and then the service manager before they replaced the hitch, but they did so at no charge and even gave us a free rental car for four days while the hitch was on order.