Well, some do. Especially the newer ones. It does depend on what the boot is designed for of course. A garrison boot for wear on base might have padding where an actual field boot might not. Part of the reason could be blamed on the innate conservativeness of the military when it comes to change. Used to be that hardly any shoes had much padding in them. But the main reason has little to do with that or with miserliness but more to do with hygiene, durability and even comfort. A permanent pad can get compressed with wear and develop a permanent set which can be uncomfortable or even unhealthy by causing wear back onto the foot, blisters, and open wounds. The permanent set may no longer pad the boot or become worn or torn rendering the boot, which is otherwise fine, unusable. A permanent pad can become water logged causing all kinds of foot problems, mostly fungal like trench foot, athletes foot, or its evil big brother jungle rot. There are of course removable pads which alleviate some of those problems. In the field especially with mixed troops who may be wearing several marks of boot there may be logistical and supply problems with those pads as they have to be made to fit a particular style boot. The military's answer to those and related problems is just the common ol' sock. Well, common as opposed to some esoteric super duper pad, the military sock has to meet all the specs making them a major drain on the economy, maybe not a major drain but Sock, Tube, cotton/nylon, terry lined, one size, black costs 3 bucks surplus while I can get 3 pair for less than that at Walmart. Anyway, back to the sock instead of padding. When socks get wet or compressed they can be changed. If there are any to change into, in the days of the steel helmet, the outer shell was often used as a sock washing basin as well as for boiling coffee (one should pay attention to precedence here). There is an old photo of some marines on some pacific island hunkering behind some shell blasted palms, several of them had socks fastened to their helmets, I thot it was some bizarre camouflage till my dad told me they were just trying to dry their socks. There is a Willie and Joe cartoon where they are talking to a war correspondent in a rainy shell crater, Joe is saying, "What am I fighting for? A pair of dry socks that's what." I've also read of nonsmokers trading the C-ration cigarettes for socks, which cost more packs than chocolate or even coffee. But let us return to socks instead of pads; The sock procedure, which is a good idea for anyone who wears hiking, hunting, or any other boot while out in the boonies, requires the wearing of boots a size, or even more, larger than your usual shoe. Originally it required the wearing of two or more layers of different kinds of sock and the carrying of at least one set of spares. Nowadays there are socks with the layers all built into one sock, each method has advantages and disadvantages. The inner sock should be a thin non-binding, non-rubbing, non-absorbent material. Nowadays it is a synthetic but the Red Coats who fought against Washington were issued two pair of silk stockings. The non-rubbing allows the sock to slip inside the next layer rather than the foot to rub against it. The non-absorbancy is more important, it allows moisture from the foot to pass on through to the next layer which is absorbent keeping the moisture from passing back to the foot. That absorbent layer is also thick to act as the cushion or pad, usually wool as that has the quality of remaining cushiony even when wet, absorbing a lot of moisture without becoming sodden and also of releasing its moisture to the last outer layer. Sometimes cotton is used for the second layer but it does not work as well in wicking away water, absorbency, or resistance to compression. That last layer is also usually wool but thinner than the second layer, sometimes cotton is used but it does not wear as well. The moisture wicked away from the foot evaporates in the last layer. This three layer system also works to keep water from outside getting to the foot, sorta. A disadvantage of the three sock method is that it requires carrying more spare socks. The advantage is that it works better than the 3 in 1, and it might not always be necessary that all socks need to be changed, if wading thru a puddle only the outer layer becomes sodden, that sock might be all that needs changing. If the middle layer gets sodden, it can just be dried out without a good washing, the inner sock keeps the dirty sock away from the skin. And, especially in the military, the socks can be those one size fits all tube style. The modern 3 layers in one sock is made of synthetics and synthetic blends which may or may not work as well as the old natural fibers, depending on who you believe. The various types of fiber can be put where they are most wanted, more cushioning under the foot less around the toes to allow for movement, more slippery against the toes but less under the foot for traction; you don't have to carry so many pairs; its quicker to change one pair than three. Disadvantage are that they cost more, if one layer gets too wet the entire sock must be changed, and if one layer is shot the entire sock is shot. And because of the placement of the various fibers more attention needs to be paid to actual size. But of course you know that "one-size-fits-all" means that it fits as poorly as anyone as it does on everyone. And there you have it, what you should have learned long ago. Like I did when I found that picture of them Marines in that "Real Man's Action Photo" magazine and my Dad set me down and had a frank discussion about sox. No, wait, that's not what that discussion was about and it wasn't that picture that instigated it at all, tho I think he said something about protective layers. BTW The War Crimes Tribunals have still not reached a decision on whether or not a GI changing his socks and then lobbing the dirty ones into a pill box violates the Geneva Conventions regarding chemical and biological war fare.

Modern military boots have lots of padding, between the tread and the insole is soft rubber layer that is between 1 and 2 inches thick, and absorbs shock pritty well. Then, in the boot there is a small insert just like you would find in a running shoe or hiking boot. Here is a pic of my boot, with the insole padding taken out. http://i38.photobucket.com/albums/e106/snowprokt22/P1000458Small.jpg

most newer boots are built to have more padding... however if your son, daughter or friend is in the US Military & have to march or hike alot get them to goto the PX and buy extra padding soles for those boots...