WiFi Router Worm Threat Modeling

Joel Hruska of ArsTechnica writes, "Historically, the vast majority of trojans, worms, and viruses have targeted the (Windows) PC. Attack and propagation methods may have grown more sophisticated, but the PC has remained the focus of most malware. According to a paper written by a team of researchers at Indiana University, however, this could change in the future. According to the team's research (PDF), an attack that specifically targets wireless routers and spreads between them at any point where coverage overlaps could quickly and easily propagate throughout an entire city."I read the research paper, and while it's heavy on theory/research, it doesn't have me convinced that this is a huge threat.  What is the incentive for router hacking?  DNS cache poisoning?  And how does a router manage brute forcing against the others?  Can platforms cross-hack?   At least the fix of pushing the reset button is easier than reinstalling an OS.