I think you missed the point. Its the same as me asking about the drab prisons you live in. Not to mention your cherry picked examples don't really hold up. A 2500sqft home filled with natural gas has a different explosive potential than a small apartment. I am also not sure it makes sense to build homes expecting for a natural gas explosion, not even a measurable risk. You can absolutely build a home that is fire resistant which most modern homes in fire risk areas are.
Even single family homes are built from bricks and cement. Even large ones.
It's not just gas explosion, it's 'everything', fire, structural rigidity (only ground floor houses are rare, almost non existant here), and well.. they're built to last.
https://www.metropolitan.si/kronika/tovornjak-trcil-v-hiso-s... <- a truck hit a building, and old one, and you can see the damage... one wall. The girl in the room survived.
I mean... again.. you could build a home that is "fire resistant", and we do, but most americans don't, as we see in LA.
A lot of people do, in fact, talk like that about eastern european homes (them selves included).