Security will have a wider scope by default (unlike natural phenomena, attacks are motivated and can get pretty creative after all) but there will still be some boundary outside of which "not my problem" applies. Regardless, it's the same fundamental thought pattern in use. Repeatedly asking "what did I overlook, what unintended assumptions did I make, how could this break".
That said, admittedly by the time you make it to the scale of Google or Microsoft and are seriously considering intelligence agencies as adversaries the sky is the limit. But then the same sort of "every last detail is always your problem" mentality also applies to the engineers and software developers building things that go to space (for example).