The insane rent increase is a more “modern” thing in European cities. I put modern in quotes because it still goes back more than 20 years, but in many places rent hasn’t increased much for the people with old leases.

In some buildings the owners have found ways around the rules, like selling the building to investment funds with enough money to tear it down and build a new one. Or maybe made enough renovations to make larger rent increases legal, but some building owners seem content to just get the steady income without doing much about it.

The big rent increases mainly come from all the new or completely renovated buildings and those are mostly owned by large investment companies.

I personally hope we eventually get enough grip on our cities to tell those investors who are foreign to go fuck themselves and seize their buildings, but it’ll probably take some time until we get to that point. Or maybe it won’t, around 30% of the population supports it or something similar.

Yes, yes, I know this is communism and will bleh bleh bleh, but we can’t keep letting the wealthy herd the poor around like this and expect our society to remain positive about our democratic ideals.

Well, you either tax the land to reduce its value to investors or you don't let people own land in the first place.

No, you can prevent certain types of land ownership. Which is the second one, but it's more nuanced than "don't let people own land."

The real issue I think is that modern wages can't support the cost of new construction. If they could people would simply build more houses themselves.

I'm not sure it's fair to call telling foreign investors that they're not welcome to use your country as a rent farm is fairly called "communism." Until the rise of neo-liberalism that seemed to be a pretty core part of all economic populism on both the left and right.

It is more extreme in Berlin, but I think in general the spread between new rent and old rent is very high.

I.e. in Munich, the average rent per square meter is about 10€, while the average for new offers is almost 17€.

This is a problem because nobody is moving out of their places, so people get stuck in the wrong flat. Old people won't leave their too big places after their kids left, young people with kids live in places that are to small.

(No shade thrown at the old people, I'd also not want to leave the place I lived in for so long. But on a bigger scale, it's an issue.)

I believe Switzerland has a similar approach.

Anecdata #1: a long-established barber shop paying a fifth of the rent that the very similar empty unit next door was advertised for.

Anecdata #2: just too many ‘businesses’ which offered little of interest and which never seemed to have any customers; some shops even only opened for a fraction of the year (eg those selling Fasnacht regalia).

Switzerland also has the 'hobby-business' problem, where a rich housewife wants to have a fashion brand or something similar. Walk through Niederdorf in Zurich for an example of what happens when this takes over...