In this case, the answer is that Apple didn't come up with the idea. A startup (FingerWorks) invented multitouch trackpads and sold them. They were originally

In this case, the answer is that Apple didn't come up with the idea. A startup (FingerWorks) invented multitouch trackpads and sold them. They were originally marketed as an alternative mouse technology for people suffering from RSI. They were rather expensive at the time (~$130), which is probably why they didn't have much mass market appeal originally. Apple bought FingerWorks to get the patents. The "new" trackpad from Apple is essentially a reimplementation of the iGesture pad with some modifications. Specifically, it's now cordless, there have been some cosmetic changes (color and shape), and they've made some changes in the mapping of gestures to operations and added some new gestures that weren't in the original product.