Yes tablets had existed in the past but did any of them have scaled down, touch optimised UIs?
Yes. None of them were widely commercially successful though. Products that come to mind include the Crunchpad (which I'm not sure actually made it to market), the Always Innovating Touchbook and the Pepper Pad. Of these, the Crunchpad was most similar to the iPad.
So no, Apple didn't invent a new product area with the iPad. They were just the first to find commercial success in that product area.
Yes. None of them were widely commercially successful though. Products that come to mind include the Crunchpad (which I'm not sure actually made it to market), the Always Innovating Touchbook and the Pepper Pad. Of these, the Crunchpad was most similar to the iPad.
So no, Apple didn't invent a new product area with the iPad. They were just the first to find commercial success in that product area.