Seconding this!
I was just in London, England and had an opportunity to visit an enormous Harry Potter exhibit over at Warner Bros Studios. Several airplane hangers full of props and settings, plus a backlot - it's an entire day's worth of things to see, with a break halfway through for Butterbeer.

It's been open for years - and it's still packed! We met people who'd travelled from Texas, especially to see it.
Harry Potter is a lot more than just a series of movies. For us, it was the first novel my daughter fell in love with. I remember her sitting on the couch with the book (before there even was any talk about a movie), saying, "This book makes a Harry Potter movie happen in my head!"
When we first stepped into Hogsmede in Universal, she literally cried. There's nothing else that can even come close, for her, to the experience of a childhood fantasy suddenly made real.
And there's a whole generation of kids, just like her, who grew up with these books. And they'll pass their love on to their kids, and their grandkids. Harry Potter will no more go out of popularity than Mary Poppins or Peter Pan. It's one for the ages!