https://en.wikipedia.org/wiki/Economy_of_the_Socialist_Feder...
High unemployment, billions in US foreign aid, etc.
I'm not sure we're reading the same article then.
Here's some archive footage from 60's Yugoslavia for your reference: https://www.youtube.com/watch?v=YXr5aKZ8mps
Sure doesn't look like people living in squalor in their mud huts.
Those all come from economic powerhouses.
The steps from mud huts to modern buildings came from economic powerhouses.