So given sufficient foresight, the prospect of a 1980 punishment hurts the 1950 owners, even if they sell in the interim.
After a punishment in 1950, the owners will be rewarded in 1980 if they sell soon enough.
mnli hypothesis: After a punishment in 1950, the owners will be rewarded in 1980 if they sell soon enough. premise: So given sufficient foresight, the prospect of a 1980 punishment hurts the 1950 owners, even if they sell in the interim.