There is a difference between intrinsic value and price. The former, of course, cannot be determined conclusively to the third decimal place. But at a price of €450, you don’t want to end up with a value of half that.
The problem is that the mentality here is that land and soil are not to be sold. That stays in the family. People would rather leave good building land undeveloped for decades and happily pay property tax on it.
Don’t let yourself get crazy. Fatalism is the worst thing that can happen to you in the search, whether for a building plot or an existing property. Once you believe that price and value are the same, you have a problem.