Part of the impression that iOS is dominant comes from usage stats. Last I had insight into the stats (maybe three years ago? Four?) iOS users spent way more time using their devices than Android users, it had been that way basically since iOS and Android had existed, and that state showed no signs of changing. Web browsing? Average iOS user does more of it. Time in apps? Ditto. So they have a much larger usage footprint, are more visible in hands as you're out and about, et c.
