The city of Vienna has a fairly unique history. It used to be the capital of a massive empire that's now gone, and thus suffered a period of fairly prolonged decline.

It's population declined from 2.4 million in 1914[1] to 1.5 million in the 1980s[2]. The only reason why it's currently considered even close to a world-class city is that after the fall of the Berlin wall it was the natural financial hub for oligarchic capital.

I think we can all agree not many great and global cities have tons of free housing emptied by a prolonged period of decline. And that we can't really evaluate if the city is solving the economic problem well or badly, as right now it's simply less acute for historical reasons that have nothing to do with it's housing policy.

[1] https://ww1.habsburger.net/en/chapters/growing-city-vienna-e... [2] https://www.macrotrends.net/global-metrics/cities/20107/vien...

> I think we can all agree not many great and global cities have tons of free housing emptied by a prolonged period of decline

That is not the case in Vienna, either. The government built enough units to supply ten percent of the total market and used that leverage to drive down prices. Before that, a large portion lived in squalor.

> But from 1923 to 1934, in a period known as Red Vienna, the ruling Social Democratic Party built 64,000 new units in 400 housing blocks, increasing the city’s housing supply by about 10 percent. Some 200,000 people, one-tenth of the population, were rehoused in these buildings, with rents set at 3.5 percent of the average semiskilled worker’s income, enough to cover the cost of maintenance and operation