> "or there will, sooner or later, be a breach of their poorly secured system."

It doesn't even need to be poorly secured. The oldest form of hacking is social engineering. If a company is storing valuable enough information, all one needs to do is compel the lowest common denominator with access to it to intentionally or inadvertently provide access.

You can try to create all the sort loopholes and redundancies but in general the reality is that no system is ever going to be truly secure. Another reality is that many of the people with the greatest level of access will not be technical by nature. For instance apparently the DNC hacks were carried out by a textbook phishing email - 'You've like totally been hacked, click on this anonymizer link to leads to Goog1e.com so we can confirm your identity.'