The author should have calculated the time dilation: the data given doesn’t make sense. The velocity of the space ship is stated to be 0.8 c. Elapsed time at Earth was 20 years and ship time 2 years. Actually the ship time would have been 12 years. Also, it is very unlikely that you could find something which would rise its price in only 20 years so much that you could retire on its profits, even factoring in the (decreasing) novelty factor. And it is possible to take only one single thing with you? And the returning astronaut is unemployable? What, are they going to scrap the ship used on the trip? His experience on it should be useful.