Why Does AA Announce Gates Well in Advance?

On a recent coast-to-coast flight connecting in DFW, AA changed our arrival gate in DFW twice, and my connecting gate once, during the course of my first flight. I realize that last-minute operational issues arise, but in my experience, AA changes gates much more frequently, and closer to departure, than UA or DL.

If that's AA's approach, then why announce a gate -- at least at a hub -- more than a couple hours in advance? If passengers (especially those with paper boarding passes) don't check for updates, they may rely on stale info.

European carriers often don't announce gates until just over an hour before departure, so it's feasible.