I don't really know what I'm looking for either, I just know that these product categories looked like they had lots of companies that tried to make it big and failed (or somewhat succeeded in the case of companies like Blackberry, but not on an Apple scale), while watches look like they haven't really tried.

I saw almost nothing of smartwatches before Apple's. I think I saw one two or three times in the world, and always at technical conferences. MP3 players and tablets, while far from ubiquitous before Apple's entry, were things I saw at least semi-occasionally out in the world. Smartphones were relatively common, although of course nothing like how they ended up being after Apple came in.