There is a "symbiotic" reason for strings to be thicker for lower tunings. A thicker string provides more surface area and therefore more raw sound (presence) as needed for a listener to hear tones as the same "volume" (even thought they are not). A thicker string also povides the necessary physics to compensate for the different tension that would be required to apply to strings to achieve different notes... usually more tension for a higher note... yet a thinner string requires less tension to achieve that note... so the tension across strings/bridges are (theoretically) equal. As for reality...well...
In countries that drive on the (left) opposite side of the raod as USn's do (on the right) are the operation pedals arranged opposite as well... making then from right to left... clutch-brake-gas? Are all cars alike. Where's our Ruby?
