Likelihood is certainly a consideration, which depends on a number of factors. At the moment, lack of publicly available exploit code will also protect you, as well as proximity to your WiFi signal.
However you are simply wrong about the need to patch your router. You don't have to take my word for it (having worked as an offensive cyber security expert for the past 20 years), you can also read any article on the subject.
Here is a pretty good one:
http://www.iflscience.com/technology...acker-attacks/
I am only correcting your statement as I consider that some people might actually listen to your advice and not take the correct actions to remediate this.