Aren't there safety conformance tests that every car is put through before being allowed to be sold? I seem to remember looking through these last time I bought a car.
Yes, but in the US at least (I don't know about anywhere else, sorry), it's way too easy. If I remember correctly, the test was made for cars back in the 60s and basically every single car gets a 4 or 5 out of 5. If you've got two 4/5 cars, then one of them will surely be safer than the other, but unless the car is able to get a 5/5, there's no difference in the score.
The tests have evolved a huge amount since the 60s. And even if a car just barely met the minimum legal requirement to be DOT legal, if it performs poorly on the IIHS tests then people are going to run the other way. And once your brand has -that- reputation, good luck coming back from it anytime soon.