For context, the majority of lawsuits in construction involve defects that are far from life threatening. Waterproofing, insulation, or, say, windows not working quite right are more common. There could be millions of dollars at stake because a defective building is worth less as an asset, but there are rarely lives on the line.

I don't think many architects would be comfortable taking risks with critical structural details. Also, even if a firm isn't found technically liable for a deadly building failure it can still be very bad for business.

That said I'm sure some architects still put people's lives at risk to avoid liability. I suspect it's similar any other industry where, sometimes, collectively people in a company put the public at risk for the sake of financial gain - pharmaceutical companies, manufacturers, mining companies, etc. No individual feels personally responsible.

Typically an architect's design would need to be signed off by a structural engineer before construction begins. The structural engineer would take on the liability for safety critical aspects of the design.

The architect and engineer would presumably collaborate to ensure that the design is at least clear enough to be safely built.