The Harry Potter movie franchise was nearly as big as the books themselves as far as their pop culture influence. And if nothing else it did something unique in the way that it introduced a host of young actors that audiences got to watch grow up before their eyes. Daniel Radcliffe, Rupert Grint, and Emma Watson, were unknown prior to the series, but now they're all household names, and Grint says that experience which they all share, which nobody else does, has bonded them together to this day.
No other film franchise had ever attempted to do what the Harry Potter movies did. Eight movies were produced over the course of about a decade, telling the complete story. Harry Potter and his friends are introduced to us as 10-year-olds and by the end they were all adults. Because no movie had ever done anything quite like it, certainly not to that extent, no other actors had ever been through what Daniel Radcliffe, Emma Watson, and Rupert Grint had. Grint tells Esquire it's like being in the space program...
It was a very unique experience that we all went through. And no one really understands it and can relate to it but us. Almost kind of like astronauts. Kind of a weird experiment, I think.
It may seem like a somewhat extreme comparison but it fits. Most of us have never been to space and never will. We certainly haven't been through the extreme training required to go there. If we spoke with somebody who had, it's likely we'd have difficult really understanding the experience. And that's what Rupert Grint thinks about his experience spending a decade of his life making the Harry Potter films.
There were dozens of people who spent that same decade making those movies, both in front of the camera and behind it. But Rupert Grint, Emma Watson and Daniel Radcliffe were front and center in all eight movies in a way that nobody else was. They spent so much time together making those movies you'd have to assume that by the end they'd either be incredibly close or they wouldn't be able to stand one another. Luckily, for them and for us, they became close. The movies probably would have suffered otherwise.
Even within something like the Marvel Cinematic Universe, that has been going on for over a decade, we don't see the same people working side-by-side constantly. All the various members get breaks in between films and the pool of key talent is much larger. They're also mostly already adults, so they don't have that experience of growing up together. It seems unlikely anybody will be able to relate to the experience these three actors shared, at least until somebody tries to remake the movies.