If you follow the professional liability model used in other fields of engineering (civil, etc), the buck stops at whoever sealed the report / letter of assurance / drawings / etc). We usually call them the Engineer of Record (EOR) in my field, and they are usually someone at the top.

I'm not advocating for that model in software, but it does provide a very transparent way of determining who is responsible. As the EOR, you may not design every member or do every calculation, but ultimately it's your ass on the line. I suspect it also changes your behavior when you know you are the one taking responsibility.