The term Personal Digital Assistant was coined by John Sculley while CEO of Apple when describing the Newton MessagePad, so akshually they did invent the concept.
Yes there were Windows CE devices that predate iPhone. I had a few, including the hx4700. They universally sucked.
I know downplaying Apple’s role in computing history is the cool thing to do on the orange site, but get real. The mobile world completely changed when Apple announced iPhone. We know that Google pivoted on the acquired Android OS. Would they have done so as quickly had the iPhone never happened? Given their track record, probably not.