How did The Thin Man change the focus of Dashiell Hammett's detective novel?

In Dashiell Hammett's 1934 novel The Thin Man, the focus shifts away from the mechanics of the crime itself to the playful, sophisticated banter between the protagonists, Nick and Nora Charles.1

While the book centers on a murder mystery, the actual core of the narrative is the couple's witty interactions and their lifestyle within New York café society. This shift in emphasis was further highlighted in the 1934 film adaptation directed by W.S. Van Dyke, which intentionally downplayed the novel's "haphazard" detective work in favor of the warm, engaging byplay between actors William Powell and Myrna Loy.12