Surely on cultural impact Harry Potter has to win. While GoT had a decade flash in the pan, Harry Potter is still deeply in the cultural zeitgeist. "Muggles", "You're a Hufflepuff", etc have become cemented into our vocabulary.

GoT is undoubtedly more complex, interesting world, but it never had a generation of children reading the midnight book release. That the author actually penned the series finale is also worth something.

That's what I was thinking! I was sure my parent meant GoT.

But there can't be many metrics at all where GoT beats out HP for the title of "biggest fantasy series of our time".

The Hugo voting is kind of skewed since it’s a membership thing where anyone can join but one has to be aware of it and care enough to join.