1. Lack of users answering those questions
There are very few users who regularly answer network-related questions. Off the top of my head, I can only name 3 maybe 4 users who answer them more or less regularly.
2. Lack of hardware availability
The hardware issues often require testing and having the said hardware available. Personally, I have access to only 3 wifi cards, and swapping them on and off requires time. Not a lot of users are willing to go down that route. Terminal and bash are readily available - hence more users pursuing command-line type of questions or user administration.
3. Path of least resistance
Lots of people answer the questions to which they know answers or feel confident in answering. WiFi questions require time to troubleshoot and the solutions are not always apparent unless you are chili555 who is a guru and I'm not worthy to speak his name.
unansweredquestion is a question that does not have an accepted or upvoted (2 votes?), they may of been answered in comments, were user error and never got flagged, have a 0 or - score answer, the statistics are a bit skewed. Also you lumped networking in with wifi and while, yes they can be related, they are not the same thing.