Defensive offer, or have house prices become so expensive?

A property for 1 million, 3 children each with a 400k allowance --> tax-free
Property 1 million, 2 children each 400k, minus 10% for rented property --> 3.5k per child
Property 2 million, 2 children each 400k allowance, minus 10% for rented property --> 75k inheritance tax per child

That sounds like a lot at first, but a property worth 2 million should also provide corresponding cash flows if rented. I absolutely cannot see a big disadvantage here. Whoever inherits a million can also pay 75k inheritance tax

Either use the property yourself and mortgage the property. No problem or sell and then the money is there anyway.

Inheritance tax costs more to administer than it brings in.
If someone has earned something and has already been taxed multiple times, it belongs to their family. For many, that is the motivation to provide their children with a better life and they restrict themselves because of that.
It's even more extreme with companies. If there were a 100% inheritance tax, many companies would no longer exist. Socialism only makes everyone poorer.
The consequence would be the flight to cheaper countries. Germany would lose again. We already have too high a tax burden.