general problems of the 2005 Lexus GX470

My 2005 Lexus GX 470 has had 3 door actuators replaced already, and the 4th door actuator just went bad, along with 1 of the 3 that had just been replaced. The door actuators are what unlock the automatic doors. This could be a safety issue because the only door that opens with a key is the driver door. If someone needed to enter the car quickly to assist someone at any location other that the driver location, it could cause a problem. This occurs on a daily basis and I suspect I'm not the only GX 470 owner who has had the problem. It seems that there are defective actuators being installed by Lexus and although the likelihood of injury is fairly low, it could be a problem in an emergency situation.