Again though, they do show some sort of gameplay at the end of the video
I like to think that's Pokémon's real target demo. Also they seemed more like 20-somethings to me.
I can't really give an opinion on a couple seconds of gameplay given no other context, I don't count it.
And I agree with that, I'm 20 by this point and I'd say I'm well within Pokemon's demographic still. The people who grew up playing it are still playing it even as adults, in my experience.