By that definition, most people are poor. $15 million is much more than most people have. Even split among the four children, it's fine.
The first thing I'd do is sell.
Me too. And it looks like that’s what the heirs are doing too.
But for David Lynch, I can see why he might want to live amongst the people involved in financing, making, and distributing movies. Similar to how founders move to the expensive Bay area to be near VCs, talent, etc.
You can do something similar if you buy a house and keep buying any neighboring house that comes up for sale (and renting them out, perhaps).
Uhm, it must be, or more people would do it
You'd need a little over 9% of stable returns over that 40 year timeframe to hit that $15M target.
My calculation makes that about $9m over 40 years.