If GM does something (or fails to do something) to their vehicle that causes me to crash, they're liable for the crash.
If someone cuts my brake lines (alters my vehicle) and I crash my car and kill someone, the person that cut the lines is responsible. I have to prove the context of course, and or an investigator has to do so.
And the responsible entity may refuse to pay up, may refuse to take responsibility. None of that is new either.