I guess one problem with risks on the web when compared to your house analogy is that automation can make all the difference there. For the specific MITM exampl

I guess one problem with risks on the web when compared to your house analogy is that automation can make all the difference there. For the specific MITM example automation might be less likely, but on computer networks, even very unlikely risks can get amplified by the fact that someone can just automate the exploitation. If automated drones roamed the country looking for open doors to break into, people might be more worried about their home security. Fortunately, the physical world protects us from wide-scale exploitation.