I was traveling SAN-LAX-IAD today. My SAN-LAX flight was delayed due to a mechanical, and as a result I missed my LAX-IAD flight, which I was confirmed in business class on a three cabin 777. I got rebooked on a later LAX-IAD flight, there was still F space when the agent rebooked, but I was put in economy, and not even in Y bucket. I ended up not clearing the upgrade, and arrived 4 hours later then scheduled. The agent at IAD told me there was nothing she can do because my original upgrade was "free" anyways. This is in stark contrast to what I've experienced before. I was just wondering is this something new, or is it suppose to be like this and I just got lucky last time.