Construction costs are currently skyrocketing

A few pages ago someone posted the "average income"... That may be basically correct but I would exclude the top 5-8% who earn six or seven figures, then you’d be closer to a German average salary... Even at top companies most employees don’t earn 4.2k per month....

On the topic, a carport/garage is a luxury and 120sqm is enough for a family. Where do you have storage space for bikes, seasonal clothing, garden stuff, spare tires, etc? Do you all have a basement? For the cost of a basement you can also build a 6x9m garage... The question is not cynical but I am very interested in the solution, maybe a few thousand can still be saved...

Unfortunately, that is correct.
This is due to the high, mostly fixed ancillary construction costs in DE. + land, garden, driveway, etc.
That's why I also built 40-50m2 larger right away.
I know some who build exactly according to needs and after 5 years spend exorbitant sums on an ugly extension.
Know people who spent 140k on a 30m2 extension for a children's room + larger living room.

and I know dozens of people over 60 who sit in their 200 sqm houses today and say, if only we had built 50 sqm smaller back then for the few years with the children.
Especially when after 30 years of use extensive renovations and modernizations are required. Then 40 sqm more roof tiles or 100 sqm more wall really hurt again.

Where do you have storage space for bikes, seasonal clothing, garden stuff, spare tires, etc.? Do you all have a cellar then?

Nope, I built a storage room onto the back of the carport. Then there’s a garden shed in the garden and the basement has a good 25 m² of storage space.
So I can fit everything comfortably. Three bicycles, the winter tires, trash and paper bins, and two shelves are in the carport room.
Expanded the basement a bit with shelves. Works great and I didn’t need a cellar. Also saves costs when building new.

It's still €115k less than you claim. And a kitchen is not part of the construction costs.
Garden etc. then only costs a few thousand euros, as the plot is very small. For €400k all in, you then get a nice 120sqm home with underfloor heating, extensive electrical installations, heat pump or combined heat and power plant, and otherwise good equipment.

Well, that very much depends on where you look and on the details. Some time ago, we also had a provider in our area who built a townhouse settlement like that. It was the same one as in Sinsheim.

But often sanitary equipment, flooring, and tiles are still missing. No heat pump but a combined heat and power plant. Parking spaces are not included and have to be purchased additionally.
Suddenly, you end up again at almost €500k.
Whether it’s then €470k or €530k is another question. At least, that applies to southern Germany.

And then there can be a debate whether you still call that a house in the classical sense, or more like a horizontally oriented condominium (ETW). Because there is a lot of community property, etc.

Don’t get me wrong. I am absolutely of the opinion that a large part of the high prices lie in the demands of the builders. On the other hand, I also don’t see that an "average earner" in the past would so easily have built a detached single-family house. This topic comes up here regularly. If an "average earner" did that in the past, then often it was on a plot they got from their parents, or with 20 years of paid overtime and weekends (including allowances), a lot of own work, including the village club that did the masonry and roof covering.
But a turnkey single-family house with hardly any own work (no, I don’t count painting and wallpapering) the average earner also could not have "had built" back then.

And a kitchen is not construction costs.

Now we’re starting to argue about trivialities. In my first post on the topic it says "tutto kompletto". That includes land, construction costs, incidental costs, kitchen, outdoor facilities, whatever else comes to mind and is necessary so that you can move into the house. A division into construction costs and non-construction costs may perhaps play a role for the calculation of the loan-to-value ratio. For the builder themselves it is meaningless, because you have to come up with the money one way or another. That is the only honest basis for comparison, everything else is self-deception. And thanks for pointing out that there is still quite a bit missing. The usual prefab house builders also produce a lot in series, yet even with the promotional houses you don’t even come close to 400k total costs.

Don't get me wrong. I absolutely believe that a large part of the high prices is due to the demands of the builders. On the other hand, I also don't see that in the past an "average earner" could just put up a detached single-family house so easily. This topic comes up regularly here. If an "average earner" did it back then, it was often on land they received from their parents, or with 20 years of paid overtime and work during assembly periods (including allowances), a series of own contributions including the village club that did the bricklaying and roof covering. But an almost turnkey single-family house with hardly any own contributions (no, painting and wallpapering do not count) was not something the average earner could have "just had built" back then either.

Complete agreement. Whoever wants to build "nicely" has needed the necessary cash, inheritance, or massive own contributions for over 100 years. Whoever "only" wants to feel comfortable in ownership could always do that and can still do so today – as an average earner or also with own contributions, but then with different expectations (you can see it here in the forum – there is also a dream house thread ==> there too people feel comfortable and not like second-class builders).

And then you can still discuss whether you call it a house in the classic sense, or rather a horizontal condominium. Because there's a lot of communal property involved, etc.

That is also often done here. But it doesn’t feel any different when you live in it ;) . It’s mine and stays mine, no matter what name you put on it.

And finally:

No heat pump but combined heat and power plant. There are no parking spaces included and they have to be purchased additionally.

There they are again, the desires that make building expensive – I want a heat pump, a combined heat and power plant is absolutely not acceptable. Not one parking space, but the plural is mentioned right away. Don’t take it personally, but that kind of thinking is exactly why houses get more expensive. The average earner simply wants to have their property. No discussion about efficiency differences between ground-water heat pumps or air-water heat pumps. It just should be warm and affordable.