Even Newton stood on the shoulders of giants. Iteration is innovation. Sometimes you just happen to be lucky enough to stumble on something big and important when you're iterating. But it's the same process, it only looks different in hindsight.
I was going to post this comment if it wasn't already here! Pretty much every innovation/invention that has ever occurred has been taking past inventions and adding just a small new thing. Of course, there are plenty of completely new inventions (transistors, lasers, etc), but they are few and far between.
