A huge part of the cost of developing a WiFi chip is in the firmware. WiFi is a complex set of protocols, and is especially tricky to implement in a low ram,

A huge part of the cost of developing a WiFi chip is in the firmware. WiFi is a complex set of protocols, and is especially tricky to implement in a low ram, low compute, power constrained device. There is perhaps a 50/50 effort split between firmware and hardware design. Open source the firmware and suddenly an upstart competitor has only half the cost to market, and therefore could undercut you in price.