Groundwater is a terrible thing to deal with for underground dwellings. It's a hard problem to solve. Possible, but hard.

around 40 million people live in yaodongs in China

Digging out a ton of rock and earth is a lot more complicated IRL than it is in games like Dwarf Fortress or Minecraft. Real life geology is pretty complicated, you gotta deal with shit like ground water, unstable types of earth, blasting. It's all pretty expensive and dangerous. Meanwhile humans have gotten pretty good at erecting shit above ground, we can throw up sheds and huts like nobodies business.

Edit: Also plumbing, electrical, HVAC, means of egress and sewage become problems with subterranean development. Digging a room underground, doable, but then you're gonna have to dig out additional shit to get all the water pipes and air ducts in there. Also, people like having windows, and windows are good for fire safety, but it's kind of hard to put enough windows in if only one side of a dwelling is facing the open land.

I wanna see the fucking sun

I wanna be an irl dwarf fortress dwarf ngl

Look into Derinkuyu. It's so fucking cool. They were able to do it because it was soft stone.

Keeping the water out winds up being a huge problem. Either its percolating down from outside water sources and working down through the cracks in the rocks until its inside your house or its condensation buildup from the living things inside the cave house.

Personally, I'd love to live in an underground bunker because I'm a weirdo, but i would be pretty cool with some small single story house with a reinforced shed style roof with a few feet of soil and let the crass grow.

earth-covered homes have a great climate control advantage, I'm for it in environments where it's feasible

let's do it

I'll start digging while you gather up some rugs and pillows

It's generally much more economical to build upward into empty air than to clear large amounts of earth before you can even get started building

Subnautica style underwater living facility, but we live in a shallow area.

It can be done, damnit, I know it can

real hours who up

Feel like shit, just wanna live in a hobbit hole.

some of us can live that way

looks at billionaires' bunkers

Obligatory Coober Pedy posting

poop

This is tangentially relevant, but in my conworld I'm mainly writing about one specific country, and this country was colonized by a foreign empire. A major part of the colonial resource extraction was in the form of mining, particularly open-pit mining. When economic crises led to a lot of mining companies pulling out of the colony and simply abandoning their old mines — with these crises also leading to widespread homelessness within the colony — a lot of homeless residents actually ended up carving homes into the sides of the benches of the abandoned mining pits. A lot of these homes are still around today, albeit less hazardous and with running water — and the people who live in these homes are called "troglodytes" or "trogs" or "troggies".

Hamas convinced me how good it must be there

Remembered this guy that had the manly urge to dig and now there's a group of people that are expanding the tunnels.

https://youtu.be/zmGVyzXiF5g?si=pSTCwzSoYhosVzHl

Wet

Some people in Spain used to live in Caves until the 1970's

idk, but iirc some really deadly earthquakes have been due to mass cave homes

They do in outback South Australia- https://en.m.wikipedia.org/wiki/Coober_Pedy

Radon, for starters

ROCK AND STONE!

I would like to live in a subterranean quonset hut or earthship. I also would love to just build a home inside of a mountain, though this is probably due to my inspiration from Minecraft, lol. My heart yearns to be a commie dwarf.

Moisture management probably.