Some computer manufacturers are eliminating IEEE 802.11b protocols, claiming that it will improve 802.11g.  Since 802.11n is the fastest WLAN standard, why have any legacy Wi-Fi at all?

You need a, b, and g, because not all hot spots are running n. For example, if you’re operating an MQ-1 Predator by a wireless control system, while sipping a Frappuccino at Starbuck’s (you have your fantasies; I have mine), your computer better accommodate legacy Wi-Fi networks.  If you know that your computer will be solely dedicated to a network that only supports 802.11n, then you don’t need connectivity for the older standards.

By the way, when you use your computer to conduct major combat operations from the local coffee house, be careful where you sit; data throughput dramatically decreases the further away you sit from an access point.