[MaxBarraclough]

A small fraction of software developers work on safety-critical software. Safety-critical software is (or at least should be) developed with quite different methodologies, as the cost/benefit assessment is very different regarding development speed against number and nature of defects.

If there are lessons written in blood for the development of safety-critical software, they haven't propagated to the wider field of software development.

(Disclaimer: I don't work on safety-critical software.)