IIRC, early touch screens were resistive, rather than capacitive, which didn't support multi-touch. without multitouch, no pinch. the interface has existed in movies for a long time and it just took bringing down the cost of capacitive touch screens. If Apple chooses, their size and market following allow them to bring tech to the consumer faster. That's why they got pinch to zoom first, not because of clever innovation.
It's a nice theory, but resistive supports multi-touch just fine. (Although I'm not sure that any shipping products back then actually supported it - but it's certainly possible to do it with resistive.)
But we're not talking about a patent on multi-touch, we're talking about pinch-to-zoom. I'm sure its very difficult to make a good multi-touch screen, especially one small, efficient, and precise enough to use on a smartphone. But once you have good a good multi-touch screen, it doesn't seem that hard to implement a pinch gesture. Every single demo of a multi-touch interface I've ever seen (even from before 2007) has had some sort of pinch-to-zoom gesture, it seems to be one of the first things everyone thinks of doing once you've got the capability in the hardware.