In my years of dispatching this usually comes down to one of three things. Either there was a wind bust in the flight planning software (unusual), or the pilot accepted a short cut from ATC (happens often enough), or the pilot worked out what he or she thought was a much better route using the FMS and flew into worse headwinds than planned (my first thought). The problem with using the FMS to flight plan is that it doesn't look "out" far enough to anticipate winds well down range. You might get away with it on short legs, 100-300 miles, but anything longer than that the cumulative error starts adding up. Not to mention if the pilot had just asked the dispatcher to run the numbers he/she would have would have gotten a much more accurate figure.
The good news in the story is that the pilot was professional enough to realize that while he/she might have made it to PHX, the smarter move was to realize that pushing it doesn't help anyone since there's not a lot of airfields around PHX that can support a 738. Better to pick a field and land with plenty of gas than push a bad plan.
Had the dispatcher thought that they would be below min fuel at arrival, he or she would not have released the flight, that would be a violation if the plane actually took off. The dispatcher would have pressed operations to select an airport for a planned fuel stop. Works so much better if everyone knows you are coming well in advance. Some commenters on the story thought the pilot should face an investigation. As long as a fuel emergency wasn't declared the FAA won't even bother to take a first look much less a second. No FAR was violated. As long as the original plan contained enough fuel to cover all the bases, burn, reserve, alternate if needed, any contingency if needed, then the fact that they ran into stronger than forecast headwinds is just part of flying.
The story was written as if this was a disaster averted that should have been anticipated, I disagree. I had plenty of EWR to SEA flights over the years that had to stop short because of a full load of passengers and strong headwinds. In the face of strong winds it's better to take the people and plan the stop. Usually, you have have to leave a significant amount of people and bags behind to make a big difference in range when flying into a strong headwind.
Strong eastbound headwinds over the United States are wreaking havoc on flights this week. On Monday, a 737-800 operated by American Airlines trying to reach Phoenix from Boston had to stop short of its destination in Oklahoma City, reportedly because the strong winds had nearly run its fuel dry. For reference, OKC is located around 830 miles, or 724 nautical miles, east of Phoenix.
What's the point of an open door policy if inside the open door sits a closed mind?