Driveshaft problems of the 2009 Land Rover LR2

I began hearing a loud humming noise on a 2009 Land Rover Lr2 that was coming from the back of the vehicle while driving. The pitch is low at lower speeds and the pitch gets higher as the speed increases. I took the vehicle into the dealership to find that the rear differential pinion bearing/gear was worn and flopping. The suggested repairs were at least a rear differential rebuild but may need an entire unit if damaged beyond rebuilding. A rebuild was estimated to cost $1600 and a total unit replacement was quoted at $2600. The dealership indicated the vehicle was unsafe to drive and that the driveshaft may break off at anytime. My research with this vehicle indicates this is a common problem that will eventually happen in all vehicles between 2008 and 2012. There is even a service bulletin circulating through Land Rover dealerships to notify service departments of the problem and the parts required to perform the repair. I'm concerned that a vehicle with so few miles could have a common catastrophic failure across many model years. This is clearly a safety issue that could endanger other drivers on the road and the occupant of this vehicle. Land rover is clearly aware of the problem with the circulation of the service bulletin but not recalling and repairing. I'm disappointed with the ethical decisions this company is making.