Multitasking

One question isn’t answered by many people wanting multitasking for the iPhone/iPad: Why does an device need multitasking, when the wetware in front of the device isn’t able to do multitasking at an significant scale? Just observe normal users in their habits of using computers. I assume most of them wouldn’t notice, when you would modify the scheduler in their operating system in a way that the window in focus gets all computing power, as long as you give some additional cycles to the mp3-player.