So if his father gives him the trains before death, it's fine, but at or after is not? Fun times ahead!
Also the value of model trains and the selling price are highly different numbers.
This is already law. If you gift someone your $100M mansion, they pay income taxes instead of inheritance taxes. And income taxes are higher (in that bracket).
That won't change.
Turn that around, though: Why would the state deserve 100% of my stuff, just because I died? Why can't I dispose of it as I see fit?
That's incredibly fucked up and heartless.
You should be expropriated.
Why would you deserve property?