I know we all like to poke fun at AA, and I know we all are sure we could run a better airline, but typically what is going on here is that AA doesn't want to post a delay until it's certain that there is going to be a delay and for how long it likely will be. In cases of irrops, which of course happen all the time due to weather and MX, AA ops constantly is juggling aircraft and gates. So while in this case AA believes there will be a delay due to the aircraft it currently has assigned, it doesn't want to post a 45-minute delay only to then change aircraft, or have an earlier-than-expected arrival time for the inbound aircraft, shortening or eliminating the delay, which likely would cause people to miss the flight because they arrived late expecting a 45-minute delay (and, of course, in which case folks would be on this board criticizing AA and arguing how inept they are).

If AA has made a mistake, it is to trust us with too much information about aircraft and gate assignments. Then when they change them, as they often do, we all get in a huff like they don't know what they're doing, when what's really going on is that, as much as we think we know how to operate an airline, we don't.