You also have to be fair: You’re saying this from the perspective of knowing USH. You’ve been enough to know the ins and outs, which rides you want to hit up, where you are likely going to eat (if at all), if you want to watch any shows, if you want to shop or not, etc. You can go in with a game plan and knock out “the entire park” in a few hours because you know the place. And I don’t think it’s too wild to say that that description fits for most of us on here who know this park like the back of our hands (or not moreso!)
For most people, however, USH does have a ton to do. A family whose been saving up to make a trip here can easily make a full day or two out of it (and I know people who have). A group of tourists can do it, especially if they do VIP stuff. People with kids can easily have a huge part of their day eaten up by letting those kids play in SSFL for a few hours or constantly stopping to take breaks and eat snacks.
Me, personally, I can go for a few hours: Hit up Forbidden Journey, the three Lower Lot rides, grab a Duff or a butterbeer and do the Studio Tour, Simpsons, and catch Waterworld, and that’s “a day.” But that’s the exception, not the rule, because while I’m breezing through what I wanna do because it’s a routine I know, there’s people all over the park who have been there hours before me who still haven’t done a fraction of that because they’re catching Animal Actors or SES or the wand show or spending time shopping and eating. To them, too, re-rides aren’t “boring” when their day at the park is the very first time they’ve ever ridden, say, Forbidden Journey and of course they wanna keep hitting it up while they’re here with no guarantee they’ll be back for years, or if this is their once a year/once every few years trip out here and they want to do as much as they can.
When SNW opens, I’d bet everything that there are gonna be a lot of people who see most of their day eaten up by SNW and WW alone - rides, shops, and food rather than just hitting up the rides and leaving - before even touching the rest of the park.