His exhibit at the Hirshhorn shows us how he did it. It excludes his melting watches and much of his best painting. The ocelot the painter liked to hurl into his swimming pool is missing from the show. So is his stuffed giraffe. The focus here is tighter.
Much modern art is abstract.
Dali's is insistently, painstakingly depictive. Much abstract art is big. Dali preferred miniatures. When you step into the gallery, nothing grabs your eye. Dali wasn't interested in the illusion of reality.