Well. sales of PC are down over 13% last quarter, twice as much as analysts predicted. Let's say in 4 years, a tablet would have the memory and graphics power of today's PC and able to connect to a large monitor/keyboard/mouse. But everything will be sold through an app store, including in-game purchases. 50 million gamers on iPhone/iPad/Android do that now because it's simple, fast and very easy to maintain (compared to a PC).