Construction costs are currently skyrocketing

I mean, who still buys an unrenovated house with a heating demand of 40-60 mwh?! No matter whether XPS, fleece insulation or cavity wall insulation. Everything costs at least twice as much as 12 months ago.

Families who are craftsmen or have them in the family and don't have 650k for house and land... If an old house then costs 200k and with 100k looks nice, I can probably heat the place at sauna temperature for 3 lifetimes with the remaining 350k...

I haven’t really seen the low prices for old houses either. With additional costs and 100k for renovation, you were roughly in the price range for which I am now building new. The prices for the houses were so high because the price was always determined by the person who estimated the least amount of money for the renovation. Whether they were right or not doesn’t matter.

That's true. We also once looked at a house - purchase price €250,000,

I would take any house offered here for that. Ridiculously low purchase price, no matter the condition. Such a cheap price hasn't been available for a long time.