Its a semantics issue. Is a superstar a top 5, 10, 15, 25 or 50 player?
I think a superstar is a top 5 player. Otherwise, what rank is in between superstar and MVP? So no, Kyrie isn't a superstar under this definition. Change the definition and Kyrie can be whatever you want him to be.
In this Golden State era, Kyrie is good enough to be the best player on a championship team, but only if that team is stacked with 4+ other top 50 players, in my opinion.