UPS hasn't done sweeps in years. I heard about it but it was before my time. We used to do Lear launches, too, which was during my time, but is long gone.
I think great service at any cost just doesn't make sense anymore. That's why they don't do it.
UPS has "hot" crews at maybe five or six airports across the country. There is one in ONT, DFW, RFD, SDF, PHL, and probably a few others. The crews show up, preflight the plane, and then are on a 30 minute launch window for an 8 hour duty period.
I did hot PHX for a year until it went away. It was a pretty good gig. Week on, week off, and you flew twice a week, on average.