The larger they are are the harder they fall. Reminds me of Atlas Circa 2000, global market fell and all were looking for smaller aircraft to charter. The A380 has to have a high volume charter, the 748 slips in just behind then we get into the 777lr and -f. Given this knowledge I do not think it is a concern for Boeing, as the future goes it is a small investment with small risk for the 748, Airbus fails first.