So who do you reckon is the more delusional?
Members of the public who think there is such a thing as absolute safety in aviation, or an ATC who thinks they can deliver it.
Affordable safety is not a "concept". It's reality.
That's why the response to the Germanwings tragedy was not a requirement for a third pilot to be available on every flight, in case one of the other 2 has to leave the cockpit to use the toilet.