Well of course the bbc article does not mention crash test falsification which seems to be a fixation with many. In the second to the last paragraph, the bbc reports that there was no suggestion that the cars were unsafe, but they tested a car with components but then sold a car with different components.
In true bbc reporting, there is no information on what components. Likely more to do with emissions, but then this is a guess. I’m not a Toyota fan, but this seems a little less of a scandle than what they suggest.
Airbags are a big problem because unless there is a rear mounted dashcam, all that people know after the crash is if it deployed or not. They don’t know if it deployed quickly enough get in between the person’s head and the window to actually work.
When crash tests were introduced, the vehicles were not yet designed for them so they were good. Now many vehicles are made just good enough to pass the laboratory crash tests. In some cases this makes real world crash safety worse.