Cotton, whether it's waxed or not, is heavy and absorbs water into the fibers.  Cotton is also not durable long term, and will show signs of wear after a few uses.  We developed our upland gear to catch up with what every other outdoor industry player was already using.  We combine lightweight fibers with high durability fabrics and DWR treatment to give you a comfortable shirt or jacket that will last longer that any traditional upland top on the market.  This is gear that will never stop.