For sake of argument I'm building a 160m2 house (on the larger size for my part of Europe) and the materials and labour costs for all the exterior walls came to €15,000. Admittedly that's not a finished wall as we'll need plaster on the inside and insulation on the outside (we used clay air bricks, so in milder climates the insulation could be skipped). The same volume would need 15 shipping containers - I doubt you could even get the raw containers for that price.

Considering we'll probably be spending close to €300k in total, that's not a very big expense. It's also quite quick, it took a team of 2 people less than 2 weeks to build. So far we've been waiting 3 months for windows to be made.

I would also note that domes are solving a problem most people don't have with their houses.

Domes are a great way to maximize the volume enclosed by a surface, which is almost a thing for heat loss, but you can do almost as well with a box and adding unusable volume is a false economy.

Domes are great for creating a massive, self-supporting enclosed space ... but again, why do you need that in your house? Conventional building techniques can make you a pretty large space pretty easily, and you don't typically need to support unusual loads on top of your house.

You don't even need to make your home in a dome shape to make it out of insulated concrete; insulated concrete forms are and easy way too throw together a box with the same basic benefits.

This is 100% true and it's the reason why I think dome houses are interesting and elegant but not necessarily cost efficient.

Also, we already have a cheap prefab solution which is optimized for house construction: modular homes aka trailers. They don't have the best reputation.

Home built with portable modular 8'x40' boxes made of wood: trashy.

Home built with portable modular 8'x40' boxes made of corrugated steel: trendy.

We definitely don't talk about this enough. Trailer homes can be half the cost of a tiny home, but nobody wants them because of their reputation or appearance.

I've found the hard way that the reputation is entirely justified.

- Low quality materials (thinner walls, shittier insulation, etc.)

- Off-standard measurements make replacements difficult (everything from doorways to vent sizes are unique to mobiles)

- Both of these problems conspire to make inevitable repairs more expensive than they otherwise would be

- With the result that finding handymen to do work for you is challenging. A number of people simply refuse to work on them.

- Financing options suck (banks often won't finance them, leaving you to specialty lenders with downright extortionate terms)

- Trailer parks suck. (And also have a reputation that is not entirely undeserved)

They're cheap alright, but the truism "you get what you pay for" applies. I'd never buy a mobile home again, not even brand new.