You get a guard dog to do its job without you having to reinvent the wheel and training him. Additional controls can be placed on network devices and even ports themselves. Ahh yes Argus, nice product extremely expensive. Must have been a slap in the face for them to have their contest machine hacked recently . What good is the security on any machine if the administrators are clueless.
Same rules apply to anything mentioned in the article.
For a system to be both secure and trusted you need both secure code and additional items that provide Mandatory Access Controls, RBAC, Type enforcement and so on. This is why OpenBSD will never be as secure as Linux. Ok lets all go out and buy guard dogs for our house. After we buy those guard dogs, let's train them to actually guard, but since the guard dogs may not be enough, we'll need to also hire some armed guards for the task. Since the arm guards may also be in danger, we may also want to look into hiring more armed guards to protect the others.