Vienna keeps getting brought up in threads like this, but one fact is that the demand and supply is not completely off-kilter there like in some (many?) other European cities. Anywhere in Sweden, for example has a ton of public housing but a decades-long wait to get it.
In General it seems that Vienna uses both private and public developments. Public for cooling down the market, private for faster adjustment of demand and luxury property.
In Sweden they may just suffer from NIMBY syndrome or "building is capitalist speculation!" type of stupidity.
