Disney’s marketing and “legacy” is far superior to Universal’s. Many people want to go to Disney over Universal because they’ve been convinced over the decades that Universal is a second rate destination. Disney does a incomparable job at selling “magic”, “dreams” and “happiness” — and people are convinced Disney is the only place you can get that stuff.
Especially in Florida, it’s easy to make the argument that Universal is the superior destination, but at the end of the day Universal doesn’t have the Disney name and they don’t have 8+ princesses and nostalgia in their favor.
I as well simply like Disney because it’s Disney, not because the rides are better, the prices are better, etc., but my eyes are open enough to see Disney has been shaving value year after year, while Universal has at least held steady in the value they offer their customers.
TLDR: I’m a sucker for Disney, most people are suckers for Disney, and Universal may very well be creating better theme parks than Disney.