DST doesn't shift daylight hours earlier in the day; rather, it ensures that the sun rises at approximately the same time every morning, regardless of season.
Time of sunrise various much more than an hour once you are far enough away from the equator. For example, http://aa.usno.navy.mil/data/docs/RS_OneYear.php gives over 2 hours for Texas, over 3 hours for New York and almost 4 hours for Washington.
Yes, hence the "approximately." The current system is a compromise; you can't go slewing the time continuously across latitudes and day of year, at least not yet, but you can't shock people with three hour jumps, either. I for one would welcome two dimensional time zones and continuous slewing. In an era of smart timekeeping, anything is possible.