When Behind the Name launched in 1996, the competition was limited. Other name information sites were less thorough and accurate, and catered to a less sophisticated audience. While early Wikipedia was crude and lacking in data, it slowly began to catch up. Due to the sheer completeness of modern Wikipedia, as well as user habituation, Behind the Name's previously untouchable SEO was jeopardized, and the site's search ranking has started slipping, which leaves it vulnerable to a newer threat.
The existential threat is AI
Some may question the reliability of AI-generated answers, but it is immaterial when the vast majority of internet users go to tools like ChatGPT and Claude for low-stakes answers (and sometimes high-stakes ones). Moreover, the free-form nature of LLM inputs allows users to ask complex questions like "what are some Arabic-language names of Latin origin?" without need of cumbersome faceted queries.
But the greatest risk from AI is that people will simply become accustomed to getting all their questions answered in a single place. Why manage Wikipedia, IMDB, Thesaurus.com, Quora, StackExchange, and Behind the Name when you can accomplish "good enough" with much less effort?