Let's try a thought experiment.
Instead of the usual game, we'll have the players run a group of humanoid monsters located in a subterranean lair. We can call them "orcs," but any group will do. We'll assign two adult males, two young males, three adult females and four children to each player ~ and we'll say that orc children grow quickly enough that these children are all mobile on their own, though we could force one of the females to be burdened with an infant if we wanted.
We'll start by assigning each individual hit points and combat abilities according to their status. Each player should then designate one of their adults (male or female) as a "leader." Then one of these leaders can be designated the "chief." Orcs don't usually have stats, so we can forego those, making the character creation fairly simple.
Now assign some weapons and have the characters pick ten pieces of basic equipment for each adult and each young male ~ no more than two weapons, a suit of armor, and 7 pieces of whatever else they feel they'll need (including a shield), but with this limitation. It has to be something made without an industrial or academic process. No metal, no alchemy, no poison, no magic, no unusual tools, etcetera. If we want, we can argue that one of the weapons each orc has was stolen from the outside culture, so they can have a sword or an axe. Treat each article of clothing as a separate piece, so most will just wear a hide shirt that reaches to their needs.
We will also make one stipulation. The orcs have two picks. Without these picks, they wouldn't have been able to dig their lair out of soft rock. So they'll need those.
Good, now ask them to make their lair. They have to create tunnels that connect certain necessary points together: a breeding place for young (orcs are birthed from mudpits), a food-producing chamber (fungus or whatever other imaginary food can be grown underground), a place for each orc to sleep, a place to eat, a place for tools to be made, a pen for animals and one or more entrances to the outside. Give dimensions that these rooms have to be to support the lair's food/shelter needs ~ such and such an amount of space per inhabitant. Then limit the distance of connecting hallways to 10 feet per person. The animals can be whatever exists in a dungeon environment that we feel can be reasonably domesticated (lizards, salamanders, weasels, carnivorous apes, worgs, whatever we want). Fit the number of animals to the space you'll let them build.
Give the players time to draw out the lair. While they're doing so, explain that they won't be able to carry weapons and wear armor all day long, for months and months of non-fighting time on end, so they will have to store these somewhere that they can be reached in time of crisis.
Let the players devise any crude traps they want to create, giving a 35% roll per trap set of the trap going off, potentially killing one of the members of the tribe. Make sure that the players understand that any trap in a commonly used corridor (the shortest distance between any of the above required places) will mean a 1 in 10 chance of killing a random resident, from child to chief, because of its ill-considered inconvenience. Remember, too, that the traps have to be fashioned from ordinary goods. No complex rock digging, however - we're talking soft rock and the orcs only have picks.
Still, they can make pits with logs over them for daily use and fill the pits with offal or spikes (since wood is easily obtained from outside). They can make rope from the fibres or sinews of animals that will make springs and stuff. They can make doors of every variety. We might want to limit them to a set number of traps, perhaps five, ten or fifteen. Of course, anything really vicious will start to take its toll on the population of their lair, so they'll think twice about really deadly things.
Good. Now, give the players a bunch of gold and silver coins, with jewelry and gems. Give them each a minor magic item. Once again, point out that they can't carry any magic weapons with them all the time. They'll need both hands to work. Have then show where precisely all the money is hidden. Let them be as precise as they want about hiding it, so long as they keep to the rules of no special means that can be made from the tools they have.
Finally, have the players identify where their orcs are at a given time of the day. Stipulate that such and such many have to be tending the food making, the animals, the children, maintenance on the tunnels and tool fashioning. Tools are always breaking and need to be remade.
Now, attack the lair. Use the players' own characters. We could create some of our own. We may want to pick ogres or giants as our humanoids if the players are high level. Have the players defend the lair with their humanoids while the DM attacks the lair with the adventurers.
If the orcs (or whatever humanoids) are easily killed, or if the treasure is found easily, find some way to penalize the players. Get them to talk about how they could have done better. If we want, we can hinge the player's success as orcs to how much experience the players' characters get at the end of the session.
Our goal here is to demonstrate that if the players had to play orcs all the time, they would be a lot smarter about where they stored their goods or how difficult it was to get into their lair. Even the weakest humanoids could create insanely difficult lairs for a player to break ~ and the above experiment could demonstrate to players and DMs alike what to build and how to break it.
This is the sort of thing that provides empathy for both sides, player and DM alike, while vastly expanding the possibilities of presenting the game.