What primarily causes the Thai Ridgeback Dog's rarity outside Thailand?
Answer
Their long period of relative isolation from the global gene pool.
The text identifies the extensive period where the breed remained separated from the international canine population as the main reason for their scarcity globally.

Related Questions
What primarily causes the Thai Ridgeback Dog's rarity outside Thailand?In which category is the Thai Ridgeback currently listed by the American Kennel Club (AKC)?How frequently does the Thai Ridgeback typically come into season?What is true regarding the Thai Ridgeback's physical grooming requirements?Which original function specifically made use of the Thai Ridgeback's fearlessness?How is the historical development of the Thai Ridgeback in their native region described?What training consideration is essential when working with the intelligent Thai Ridgeback?When did the United Kennel Club (UKC) officially recognize the breed?What specific temperament trait necessitates careful management around other dogs for a TRD?Why must owners of a TRD often act as the primary educator and advocate for the breed?