I agree with FlyingRon on this one. Airbags aren't designed to deploy in every type of accident. I don't think that the lack of deployment (not "failure") may not be any sort of defect in product or installation.
And I don't necessarily disagree with
either you or FlyingRon.
But when airbags have deployed once before in a relatively minor accident and the airbags replaced, and then in a subsequent accident where the car is totaled these newly installed airbags do
not deploy, there is a legitimate question as to why.
The explanation is not always going to be that "airbags aren't designed to deploy in every type of accident."
That said, if the vehicle was totaled and sissy1 walked away from the accident with no serious injury (only minor injuries from the seat belt), and insurance is once again going to cover the losses, there may not be any legal action worth considering from a financial standpoint - this even if there was a problem with the airbags.
I believe it could be worth an attorney's review. It is, of course, up to sissy1.