I don’t understand the whole Harry Potter-Twilight rivalry thing

They are completly different. Why is there this constant fighting between these two series that share nothing in common? Just because a book has vampires does not give it the right to be compared to a whole fantasy series. Why is there this constant fighting of which series will be bigger and more successful? In my opinion, Twilight can never be bigger than Harry Potter. I will never see kids walking around in Edward costumes. I will never see a Twilight Theme Park. And why do some people only consider Harry Potter a childrens book and Twilight a “young adult novel”. Harry Potter contains more symbolism and a much more intricate story line than Twilight does. Sorry if this offends anyone but I am really starting to get sick of this comparison.