There has been a focus in this industry to take seats out of the air over the past 2 years or so. Part of this was a survival move because of the incredible fuel prices in 2008.
However, part of this effort was to create less available seats in order to hopefully increase the yield (price) on the remaining seats. This is a flawed theory that will not work. Leisure travelers will travel if the price is right and stay on the ground if an airline ticket price is above their comfort zone. (whatever price that may be)
Business travelers will go when they have to go. The problem during a recession is that many businesses are not doing business and they don't have to go. When the recession is over, the business people will be back.
The end result is that this airline has had problems right sizing routes (and aircraft) between popular cities and the hubs.
While it might be acceptable to cut flights down to the secondary cities during this recession, it doesn't make sense on the heavy traveled routes. With the system in place now, one flight can cancel and that can (and does) strand US passengers for days while agents search for empty seats on other flights to put the stranded customers on. Of course there aren't many empty seats available because the yield management department puts the empty seats on priceline every morning. (This would make sense if there really was excess capacity) The rubber band is wound so tight and there is no room left to handle the exceptions, changes and diversions.
This creates customer satisfaction issues which leads to unhappy customers complaining to unhappy and frustrated and powerless employees. In the end one one wins.
With all that being said, I do find it remarkable that US is able to fly thousands of flights each and every day, safely and mostly on time.
The bottom line is that 90% of everything needed is in place. It's that last 10% that keeps this airline from being at the top of the game.