U.S. troops in Afghanistan have more allies working with them in the combat zone, than was the case in Iraq. Combat casualties for these other foreign contingents are a big deal back home, especially if it's perceived that the troops did not have the best equipment. The "best" is often defined as "whatever the Americans are using." That has caused some problems, because the U.S. military is often taking all the goodies that the manufacturer(s) can produce. When other countries ask for some, they are told there will be a long wait. This is politically unacceptable to these countries. Pressure is applied to increase production (even if the gear ends up costing more in the short run), or for other suppliers, with equivalent equipment, to be found. This sort of thing expresses itself in many different ways.
For example, U.S. Predator and Reaper UAVs are much in demand by allied nations. But the U.S. is buying all of them. So Israel has stepped in and provided equivalent aircraft. The Israelis are aided by the fact that the Predator, and the success of American UAVs in general, owes much to Israeli experience and designs. The Americans acknowledge this, and the Israeli manufacturers use that to win over customers who really had their hearts set on Predators.
Another example is night vision gear. The U.S. has always been ahead of everyone in this area, and pioneered the development of battlefield night vision equipment in the 1960s. Many nations didn't bother to keep up, since they were not at war. Now their troops are, and the word gets back home, real fast, that the yank night vision gear is much better. This is largely because the U.S. is just switching over to night vision equipment that combines light enhancement (the traditional method) with thermal imaging (the more expensive approach). Manufacturers (the big defense electronics firms) have been forced to rapidly ramp up production, to avoid angering major customers, and to ship the stuff before the need disappears (the war on terror is over.)
Several years ago, the U.S. created a temporary shortage in small arms (5.56-12.7mm) ammo, because of the heavy demands of Iraq and training troops for combat. Few other nations were as deeply into the fighting then, so this shortage was a minor annoyance for a while. But now there are a lot more shortages, and the annoyance is no longer minor.