@giaco
I disagree. Every additional security improvement put in place increased the capital required to compromise the system. If it becomes prohibitively expensive for an attacker to sufficiently compromise the system, it drastically reduces the chance of compromise.
Security doesn't need to be perfect to be usually good enough.
@Demosthenes But that includes the attitude, that your fence has to be higher than your neighbour's one.
It is not an actual improvement of overall security.