The idea of a voice assistant is very general. Voice-activated and voice-controlled this-and-that has been around for years - for computers, mobile devices, you name it.
Add in the nebulous term "intelligent", and you have voice-control which can do a little more, but often not particularly well, and in the kinds of implementations where it seemed more like a bolted-on feature rather than a credible attempt at something special, that is, to the degree that its implementation would be so well done that it could be regarded as a major selling-point, a watershed moment in tech.
Apple did that. They didn't invent it. They didn't invent tablets. They didn't invent smartphones. But what they did, in each area, was to redefine the segment so radically and change consumer perception of it so significantly, that it seems like what came before was just a pale shadow (almost to the point of it not having existed) of what Apple was able to do.
There was no "copying" here. Voice-control was already commonplace. Apple just did it right. Which can mean the difference between just another "feature" on a bullet list, and a complete paradigm shift in the way we use our devices.