Construction costs are currently skyrocketing

Absolute agreement!
But the point is to make it more attractive for older people to sell the 200 sqm house and to be able to devote themselves to an attractive alternative that might also make daily life somewhat easier.
I also know this from our village: The (mostly huge houses) are inhabited by singles or couples aged 85+. That is already a problem for the market. But logically, no one has the right to demand from people that they give up their house, which, as you rightly say, was partly created with their own hands. But how do you get them to take this step of their own free will and conviction? Difficult ...

Not at all. Any other accommodation will be foreign.
If anything, incentives must be created earlier. When the kids have left home and you actually don't need the 200 sqm (which these old houses rarely have anyway). But that doesn't work either if you see that even for 2 people 150 sqm and up are built and considered necessary.
Although I think that the current price development of materials will steer things in another direction again.

Corresponding incentives could have been tackled now with the necessary redesign of property tax anyway.

For categorizing the offer:
Loan-to-value, fixed interest rate period in years? For forward: How long until the loan is repaid in months?
Thank you

Doesn't play (in my calculation for you) a big role, since there is a 10-year follow-up financing until the happy end. So only €115,000 is financed...
However, a colleague is currently having similar experiences regarding the interest rate with a good loan-to-value ratio (and otherwise also good average values).

Of course, the question is, if Hans is the only one who has secured a self-sufficient supply for himself while his unbelieving neighbors drift into anarchy and neglect, how does he defend his self-sufficient home against the hordes from the surrounding area who are going crazy from hunger and want to take advantage of his meticulous preparation?

No problem at all, we’ll just straighten out the old nails again. Putin can go to hell! Although unfortunately my late father always predicted it.

BAD HONNEF (dpa-AFX) - Because their nail suppliers no longer receive steel from Russia, German pallet manufacturers are facing an extreme material shortage. In just a few weeks, some companies could be forced to reduce their production for this reason, the Federal Association of Wooden Packaging, Pallets and Export Packaging (HPE) announced on Wednesday in Bad Honnef. 90 percent of the so-called wire steel, from which the nails used for pallets are made, come from Russia. Steel deliveries are prohibited due to the current Russia sanctions. According to the association, there are no short-term alternatives because special nails are needed. The pallet industry is characterized by small and medium-sized enterprises; there are around 180 manufacturers in Germany with an average of 35 employees. "The situation is very difficult at the moment," says HPE board member Joachim Hasdenteufel. The industry is already under pressure due to sharply increased wood costs; the price of a European pallet has risen from just under 10 euros in 2019 to around 25 euros currently. The nails add another problem. This is not about the price, emphasizes Hasdenteufel. "But about whether we can produce anything at all."/wdw/DP/zb

And for many other products, it will no longer be about the price either. Only about availability. By now, it’s already annoying to even inquire about an offer. You just don’t get one anymore. So it’s best to just ask if available and order. Anyone who asks about the price is out.

Just a quick word in defense. The elders in our village always said you must always leave an old piece of bread behind the door. Then the hungry city folks will leave again.

So I don't worry about it at all. I have some long guns, a dog, and a big wall around my property. In addition, we live in a healthy village community. And anyone who comes in with hostile intent on one side of the street doesn't have to come out unharmed on the other side. That is the advantage of living in the countryside.

And we also still have a bakery here. So in an emergency, you can still bake significant loaves of bread with wood. That way you can give something to the hungry city folks who ask kindly.

The weapons are primarily of course intended for hunting. And here with us practically everyone is a hunter.

Why should an older person give up their property? When do you consider it timely? And what does "worn out" mean? For some here, a house seems to be just a shell that one can change at will. But there are certainly people who are attached to what they have partly created themselves. Especially since people who are old now have mostly contributed much more of their own work. Memories are attached to it, one feels comfortable. Why should one give that up?

Many people live alone or as a couple in relatively large houses in their old age. By the way, "worn out" is not only a matter of taste (the tiles from 1970 are just as out of fashion today as those from 2020 will be in 2070), but above all a matter of condition. Such a house simply regularly costs money for maintenance. You can save for a few years without everything falling apart right away, but then you have a large backlog of renovations. That’s what I mean by "worn out." Timely in this case would mean passing the house on while it is still in reasonable condition.

And yes, part of the problem is that one does not simply give away a house because one is attached to it. That is perfectly fine. But if we do not want to constantly build new, we have to consider how to deal sensibly with such houses in which the residents no longer even see the upper floor. In my opinion, this is not only due to sentimental attachment to one’s own house but also because there are hardly any good alternatives for such people. One only wants to go to a nursing home when there is no other option; city apartments with tiny balconies are not a real alternative to a house with a garden.

If, as a society, we want older houses to be used rather than demolished, and if we do not want villages to constantly grow at the edges, then we also have to think about a reasonably efficient distribution of the existing living space and consider what prevents us from achieving this. By the way, I do not have a really good answer to this question either ;)