It sure is easy to throw lots of CPU processing power at the problem and get a fast router. But for $40 less, the Nighthawk additionally includes 2 WiFi chips,

It sure is easy to throw lots of CPU processing power at the problem and get a fast router. But for $40 less, the Nighthawk additionally includes 2 WiFi chips, a whole lot of software engineering and a probably much lower power consumption due to specialized hardware e.g. for NAT offloading.