The routing of the LAX-SYD flight is just south of Hawaii. On my last nonstop from LAX the plane flew about 25 miles south of the Big Island. If DL could get the route authority, it could do HNL-SYD service with a 767-300 until it had longer range aircraft for a nonstop from the mainland. Until last year Air Canada used the 767-300 to fly Vancouver-HNL-SYD. When they got the new 777s, AC discontinued the HNL-SYD flight, and now fly nonstop from the mainland.
SYD is a big gap in Skyteam from the US. Korea is an option, but that is real round about.