Like, if I am living in a home worth $250,000, and the owner passes the home to his kid to prevent it from going to me, it could cost $225,000 in extra taxes. Congrats, you can keep the house, but you'll never profit.
Or they could sell the home to me early, and even if I only give them $100,000 it's more than they'd get from keeping the home and renting it more.
And if they just wait, I get the home free.