I have 8-year old twins that are heavily into both Star Wars and Harry Potter. I'm also one of the biggest Star Wars fans that you'll ever come across (although I enjoy Harry Potter, too). My personal observations:
- There are definitely more Star Wars fans in terms of sheer numbers. Part of it is that there's simply a lower "bar to entry" where there are a lot of casual Star Wars fans that have seen the movies or maybe even haven't seen all of the movies yet are familiar with the more famous characters. Being a Harry Potter fan generally means having had the time commitment to reading a full set of full length books as opposed to just solely watching the movies, so that will always be a limiting factor by comparison.
- Further to my last point, my kids knew who many Star wars characters were (e.g. Yoda, C-3PO, R2-D2) when they were still crawling and they started playing with Star Wars toys several years before they even saw any of the movies. In essence, those Star Wars characters are as accessible and familiar to the very youngest kids in the same manner as Mickey Mouse or the Disney Princesses. That generally doesn't happen with Harry Potter since that property doesn't have the same merchandising and toy presence as Star Wars (at least in the US) and HP interest usually coincides with getting to a certain reading level. Many people have noted in this thread that people from Generation X (like me) and older are more familiar with Star Wars compared with Harry Potter, but I think that would also be true with the younger kids (e.g. age 10 and under) that WDW specifically targets, as well.
- That being said, the average Harry Potter fan seems to be more invested because, as I've noted, the sheer time commitment to get through the books (plus watching the movies on top of them) is a much higher bar to entry than watching movies alone. The interest in Harry Potter also ramps up quickly once kids are old enough to actually read the books. My kids had very little clue about Harry Potter a year ago, but once they started reading the books over the past, they've become as much of Harry Potter fans as Star Wars fans. In that sense, Harry Potter is actually a great fit with Universal's target audience of older kids. There's an immersion in the world of Harry Potter that comes from reading that's at a different level than what you get from only watching movies.
- I'm not surprised about the anecdotes from the UK that Harry Potter merchandise is pervasive there. HP is probably the single biggest cultural export from the UK since The Beatles and, as a result, is looked at as THE franchise above all others in that particular market. In the US, though, no one should fool themselves into thinking that this is even a contest on the merchandising front: Star Wars is the single most ubiquitous merchandising phenomenon in America out of ANY intellectual property out there and it has been so for the past 4 decades. If you walk into any Target, Wal-Mart or Toys R Us in the United States, there WILL be a massive section devoted solely to Star Wars toys and several other sections featuring other Star Wars paraphernalia (e.g. clothing, linens, kitchenware, greeting cards, party favors, etc.). Of course, the one caveat is a bookstore like Barnes and Noble (which someone else mentioned in this thread) since Harry Potter is the largest publishing franchise of this generation, but outside of that sphere, Star Wars is THE biggest merchandising IP out there in the US (even more than Disney's other properties).
In conclusion, there's nothing that compares to the sheer scale and numbers of Star Wars fans out there. Harry Potter is one of the few IP franchises that comes close, but it inherently has limiting factors (e.g. a higher "fan" bar of entry with books, less familiarity with both older people and the very youngest people, etc.). However, there's a different level of intensity with Harry Potter fans that Universal seems to have tapped into very well. The Harry Potter IP also does have a natural advantage in a themed land in that there are a handful of core locations from the books and movies that Universal could focus upon and do correctly. The fact that Universal has generally received rave reviews from Harry Potter fans that are poring over every little detail is a testament to Universal (and also how having J.K. Rowling intimately involved in the process was critical). It will be interesting to see how Disney pulls off having a "neutral" setting for Galaxy's Edge that isn't rooted in an actual place that we've seen in the Star Wars universe. Star Wars is without question the bigger IP compared to Harry Potter, but whether that translates into a better themed land remains to be seen.
