There are no scalpers generally, as Recreation.gov blocks them (you can also tell because no one sells tickets secondhand), it's just that supply is very very limited, this is an area with millions of tourists and residents and only a hundred or so tickets released per day. Beyond that, it's just luck.

Securing tickets for the Washington Monument is notoriously difficult primarily due to the extreme disparity between high global demand and the very limited physical capacity of the monument's elevator system. Unlike an open park, the monument is a narrow hollow obelisk; the elevator can only transport a small number of people every few minutes. The National Park Service (NPS) strictly limits the number of daily visitors to ensure safety and preserve the historic structure. Tickets are released in two windows: most are available 30 days in advance, while a tiny "last-minute" batch is released at 10:00 AM the day before. Both batches typically sell out within seconds of becoming available on the Recreation.gov website. Furthermore, the monument is frequently subject to unscheduled closures due to high winds, lightning, or elevator maintenance, which further reduces the available inventory. Because it is one of the most iconic landmarks in the United States and offers the only 360-degree unobstructed bird's-eye view of the capital, thousands of tourists compete for only a few hundred spots daily, making it a high-speed "digital race" for anyone planning a visit to D.C.