If it had that many guests it'd be ahead of Epcot in the theme park rankings. We can all agree there's not 45k in USH on any sort of regular basis.
And on a similar note, Epcot can sustain 80k guests, 120k is every possible venue is open, every bypass path, every everything. It only goes to around 90k, once a year, before they shut it down (That's NYE.)
15-20's, with a peak day around 25 or maybe even 27km is entirely in line for USH attendance.