[FabHK]

As an overseas (or even domestic) tourist, you might be quite time constrained, and then, naturally, you'll go for the most famous ones within the vicinity.

This "long tail" phenomenon is at work elsewhere, as well: I've been to the Angkor Wat complex in Cambodia recently for the third time and took some time to explore more remote ruins (Koh Ker, Beng Mealea, etc.), and while the main sites (Angkor Wat, Ta Phrom) are visited by busloads of tourists, you can easily be the only person for a while at the more remote ones.