Typical disclaimer: I’m not a flaired user but I used to be flaired user on this sub (my comment history has my previous answers) so I hope it’s okay to answer this?

I don’t have any evidence of this, but the most probable answer is that the Ancient Egyptians are more well known. They are generally taught to children at an early age and most people know at least something about the pyramids/pharaohs/hieroglyphs. They are also the last remaining ancient wonder of the world and most Egyptian tourism is based around visiting the pyramids/sphinx/valley of the kings etc.

The pyramids are fascinating to study and see because they are so well built. They are aligned to the stars and the sun and are constructed in absolute perfect symmetry, with tools far more advanced than anything else existing at the time. They aren’t hollow either, with miles and miles of channels and chambers housing the riches of the pharaohs.

This isn’t to say the Arab treasures you speak of are not fascinating, but I think it generally comes down to people simply knowing of their existence because it’s quite an easy topic to teach children.