I would say it's because a good majority of people prefer a hard-wired internet connection for maximum reliability and minimum ping time. I know I certainly wouldn't want to game over a wireless connection.
Well considering everything else on my computer is wired and there is an ethernet drop about 3 feet away and i didnt spend a ton on my wireless router it would screw me up more just doing normal web browsing than the 'inconvenience' of having another wire coming out the back of my computer. Unless you spent a bit getting a good reliable wireless router its not even worth attempting to game over wireless, hell my internet dropped out twice while i typed this.
Wireless is not built-in on most of the rigs discussed here. Laptops and All-in-ones typically have wireless built-in or included in the base configuration, but their owners don't bring their problems here.
On-line gamers are almost always competing, and impossibly small fractions of a second do matter.
Many routers/adapters certainly "do the job" well enough for non-gaming applications, but reviews on extreme performance parameters are hard to come by.
Message edited by Twoboxer on 08-26-2009 at 12:58:03 AM
Even the expensive gamer motherboards do not generally come with wireless cards. Instead, you might find a SLI motherboard with two 1000MBit LAN cards, but not a single wireless card. Fact is, wired/optical connections outright beat wireless connections with speed and timing (ping).
I think a lot of people get and use wireless cards for their rigs (I have a a PCI Linksys g card) but like keyboards, mice, gamepads, etc are not included in build discussions, as they are thought of as more accessories to add on later.
I prefer wired, but it is nice to have options, especially if your desktop is in a large house.
Most people don't offer advice on keyboards, mice, wireless cards, etc... unless the OP specifically asks for help with those components. Those aren't really considered core components in a build. Questions about wireless cards can be better answered in the Networking section of the forum.