Ignition Switch problems of the 1999 Lexus RX300

I own a 1999 Lexus RX-300. The keys are defective, resulting in a dangerous condition. Lexus's dealers and its "roadside assistance" personnel have told me that the keys were originally made with metal that is too brittle. As a result, the keys grind down, and eventually the keys can come out while the car is on, or can come out before the lock is disengaged, making it impossible to start the car. Lexus has issued internal technical bulletins, but has never advised its customer of this problem, which results in a $900 repair problem after about 4 years of use. Keys should last more than 4 years, or Lexus should be forced to advertise that fact to its customres.