> But are you able to buy a decent detached house with a backyard and ...
You would need very thick reinforced concrete to be sure of surviving most tornadoes. And you'd have to solve the roof problem.
You are severely underestimating the power of tornadoes.
Several have been hit by tornadoes. There is even an older design (thinner with less reinforcement than modern designs) that survived an EF4 or EF5 tossing cars at it.
> No standard home construction even with brick
Regardless of the sheltering advantages of dome homes, it's misleading to say they're just as affordable. They don't resell well at all, making it an extremely risky investment. Costs of the basics (as told by the marketing documentation you sent me) can be just as cheap, until you realize you lose significant floor space and you need more materials for a similar sized home and you realize nothing standard fits. No nice doors, no normal windows. Now you need custom ones - price goes up.
Compared to the homes rebuilt after disasters, most of those are significantly cheaper to build than a dome and that's where insurance goes. People aren't willing to pay more for a non-resell-able and frankly ugly structure that isn't as practical.
Each room in a dome home will normally have at least 2 flat walls, frequently 3. That's enough for shoving things against walls, not that you should damage your paint that way.
Usually people use normal windows and doors. You can install them the ugly way or the pretty way, and oddly there are people who choose both. The ugly way has them on bulging protrusions. The pretty way has them recessed behind openings that are often rectangles or trapezoids with rounded corners, with the space between acting as a balcony or sheltered porch.
Here is a pretty one on sale now, having gone up in value by more than a factor of 8:
https://www.islandpacket.com/news/business/real-estate-news/... http://www.monolithic.org/homes/featured-homes/the-eye-of-th...