I live in a former yugoslav socialist building, and our external walls are made from reinforced concrete. Our internal walls are reinforced concrete. Our bathroom walls are reinforced concrete. Drilling a hole to pull a network cable from one room to another is a pain.
Culture shock was big for us when we moved from 'bad socialist block of flats' like that to a new, modern and expensive London block of flats made out of cardboard. I know that my flat in old country will still be there for my wife and I to retire if we move back, while this one will probably seriously deteriorate.
I agree, cabling is a pain but oh my are they taking us for a ride with these newbuilds with easy cabling. Houses are no better here. They say these newbuilds are all fireproof and engineers come once a week to test everything. Of course, I hope we never have to find out if the certificate is worth anything.
All in all, those Yugoslav socialist buildings put these newbuilds to shame. Even those 40 year old locally made lifts are better than whatever Otis is installing into newbuilds these days. Our lift is loud, shaking. Never experienced that kind of shaking in any of socialist buildings. I suspect though that newbuilds in Slovenia these days are pretty similar cardboard boxes...
On the other hand... this are the results of a rather large gas explosion: https://novice.svet24.si/clanek/novice/crna-kronika/5be30a53... and another one: https://www.24ur.com/novice/crna-kronika/v-stanovanju-eksplo...
Fires usually stay contained to one unit for quite a lot of time, especially if the firefighters water everything from both sides (windows and doors).