So is the Amazon or Igacu Falls. So it comes back, essentially, to "Which would win a popularity contest?" which I think is a poor basis for choosing Wonders (okay, the other two aren't artefacts, but I think Igacu should be a Natural Wonder).
I see your point but this is ultimately a game isn't it. Meant to entertain us. The game also needs to be accessible to a wider audience. So if they are putting popular or well-known wonders in the game over other more culturally significant wonders, it's only because more people know about these wonders.