Nothing to do with the government- any big company will avoid fessing up to a problem until they absolutely have to. It sucks but it`s just the way big business and the almighty dollar rules over the safety of people.
Obviously cars are complex objects, and with new models and technology coming out all the time, not to mention cheaper ways to build the same part or accomplish the same task, problems happen. I would just hope that as soon as they see and detect a problem, they would jump on it and immediately redesign the part, at a minimum, and then consider recalling to replace the rest, but I would bet sometimes management refuses to even redesign a part, simply because doing so would be admitting a problem.
Decisions like those, if proven, are the worst in my opinion, and should be considered for criminal prosecution.