There is nothing to gain with not taking safety seriously, but fortunes to loose. Many of the software components of traditional automakers are built by suppliers. If a serious safety issue would arise and cause fatalities, the suppliers and the OEMs would not only have to pay enormous amounts in damages, they'd also need to issue recalls that might even pose an existential threat to the company.
The designers get together and in a formal process try and come up with every possible adverse outcome and the probability it is likely to occur.
They then rank and use this info to assign performance requirements to various safety aspects and functions.
But a key part of the overarching parent IEC61508 standard is that there is a safety lifecycle - the designers make their best guess but the manufacturer has to at regular intervals compare actual gathered data against the predicted design data used and adjust accordingly, iterating to a better place.
Just like you might win the lottery first time you buy a ticket, under a performance based standard you might experience an adverse outcome in the first day of use, doesn't mean the design was necessarily deficient.
Infinite safety takes infinite cost, which would mean no cars, and what would the cost of that be to society.
Like I said,it's all shades of grey.
I trusted Volkswagen because of their reputation. Then the news broke about them systematically lying and breaking the law with respect to engine emissions. Shortly after this came to light, other "reputable car companies" turned out to have been not trustworthy at all.
Yes there are good standards in place and some companies claim to adhere to them but no company should be trusted on their word or reputation alone. The better question is what kind of regulatory oversight is in place to make sure those claiming to adhere to certain standards are actually doing so? Also, how much power do the regulatory organizations have in addressing violators?