Look for the Temple at Amon-Re.  Note the spacing of the columns relative to their height.  The Temple of Hatshepsut is another example.  Click on each of the pictures for a larger view.
  The columns also served other purposes.   Have a look at this virtual temple to see how function was applied to form
  The Temple of Luxor is worth a visit.  Photos and floor plans emphasize the column-predominant structures of the time.  Other parts of this site are well worth a look.
  So what is a builder to do?  Building Big in the old days meant using your materials in such a way that you benefited from their strengths.  If stone is strong in compression, make the columns the focal points.  Short beam sections are used to hide the wood roof that covers the interior space.

  Perhaps you have a question related to the diameter of the columns.  Why so big?  Yes, the columns are basically supporting their own weight, but they are also resisting lateral forces imposed by wind and the occasional earthquake.  In this instance, the correct height-to-diameter ratio may have been known from previous projects or determined after one or more failures.

  Aside: In modern times, we still deal with height-width ratios for columns, but we refer to it as the slenderness ratio.  A similar ratio of length-to-width is applied to beams.  Consideration of the unbraced length of beams is part of determining how much load they may safely carry.