All this was made without heavy machinery to lay the rock or computers to create the design. It came from completely from the minds of humans captured with some sort of pencil on some sort of papyrus. Or it may have all been stored neatly in the head of the architects. And it was crafted with manual tools by artisans. It seems the simple way would be to create dull boxes for the people. However, people are drawn to beauty, people need art, art in the architecture, art in the form of paintings, art in the form of music. Without art, the human condition would seem dreary.