The insane real estate prices in some parts of Europe are mostly due (besides the monetary policies, NIMBYsm, regulations, and inherited wealth) to the scarcity of land in that desirable location, and less about the quality of what's built on it. And I'm not even talking about beach front properties in the south of France.

Ive seen many old houses for sale in Germany for ludicrous money, that you'd basically have to tear down and build something livable.

Construction costs are negligible compared to land costs in urban areas. And the cost of land is set by demand.

Construction costs have very little to do with current asking prices.

It is all about what the market can bear (and it can bear a lot these days, thanks to incessant money printing)

Build a european spec house in Dallas and it will still be way cheaper.