I've never bought this argument. It is mathematically unsound. Systems behind my firewall, touched by one or two people, and with fewer hackers trying to break

I've never bought this argument. It is mathematically unsound. Systems behind my firewall, touched by one or two people, and with fewer hackers trying to break in are exposed to fewer threats. Many people want to break into gmail, because it's gmail. Many fewer people care about breaking into one university. There's no wire over which to transmit information. The more access points there are and the more hackers there are who can reach the systems, the greater the probability that one of those hackers will succeed. Google's sophisticated systems have already been compromised by unsophisticated hackers in China. A house with 5 doors is less secure than a house with 1 door. A house with no windows is more secure than a house with windows.