> It is unthinkable to me that anyone believes there is such a thing as computer security

There is such thing but almost never a priority. In the corp I work leadership talks a lot about security but when comes to the incentives the road-map takes priority over the security. If you deliver fast you'll be promoted, if you're a paying attention to the security no-one will appreciate it and the manager will hate you for delaying delivery. Many managers I interact with see new features as the main value development teams should provide and security, reliability and other QoS as a waste to be minimised.

Another issue is that even if security will be a priority and managers will be on board (good lock changing the culture tough) we probably cannot build secure systems while keeping the insane level of complexity we have nowadays. Switching to simpler but secure system will require sacrifices in features/convenience.