There were usually more camp followers than troops, with the ratio of helpers to fighters as high as ten to one. There was a lot for camp followers to do. Pack animals had to be cared for, tents pitched, water carried, wood chopped, food bought or stolen from the locals and cooked. Then everything had to be packed up for the next march. During battles, the camp followers stayed behind in the camp, often fortifying it and using a few weapons and their bare hands to defend it against any enemy troops who got that far. After the battles, camp followers tended the injured, buried the dead and plundered the enemy corpses.
While it was much more efficient to have the troops do their own housekeeping in the field, few armies were disciplined enough to pull this off. The more successful armies did, like the ancient Romans, who traveled light. When a Roman army of 10,000 showed up, there were some 8,000 fighters with it. Most other armies could produce only a few thousand warriors. Since most armies lived off the land, and this often limited the size of the army, the force that hauled along the fewest camp followers had a substantial military advantage.
This lesson eventually was relearned, and camp followers began to thin out in most Western armies. A century ago, support troops amounted to less than 15 percent of an army. But in the last century a lot more equipment has been added. Not just things like trucks, trains, transport aircraft and cargo ships that civilians could be hired to run, but weapons and other gear close to the front that needed soldiers to take care of them. Now the camp followers comprise about 85 percent of the troops. Yet everyone wears the same uniform and gets the same pay. Combat troops get a small bonus when they are in a combat zone, but that's about it. Combat officers still get most of the senior positions, but that is starting to change because of the sheer number of non-combat officers versus the warrior types.
This change has been going on for several generations and, more and more, the generals think less like fighters and more like bureaucrats. You can see the difference this makes in the way the marines and army are becoming more different. While the army still has some rough characters in its ranks, especially in ranger, airborne and special forces units, more and more soldiers were trained to be kinder and gentler. The marines were different. All marines are still considered combat troops first, and whatever non-combat chores they might do every day as secondary. More and more, the marines are seen as the troops you can trust if there's going to be a really desperate fight.
In the past, whenever bureaucrats have been appointed to run an army, disaster arrived along with the next war. Watch for it.
Finally, after thousands of years, we are putting the camp followers in uniform. This is another of those remarkable, and largely unnoticed, 20th century military developments. Camp followers usually are thought of as loose women following an army to service the troops. There was always some of that, still is, but historically camp followers have largely been male and mainly there to do the housekeeping and keep the troops alive in the field. Battles have always been relatively rare, but the health hazards of camping out with thousands of men and horses are constant and abundant. The troops knew this, and until the last few centuries, most soldiers were volunteers of one sort or another and few generals could get their lads to rough it without a lot of camp followers to keep everyone in good health.