The price of most things falls to the marginal value to reproduce which in this case is zero. Is it right to sell the same thing so many times?

A better model would be to sell it once for a high price. Or charge someone to take the picture in he first place. It's a little dishonest to sell the same thing an infinite amount of times for a 100 percent margin.

The government can not always protect rent seekers today. Copyright is another bad law which will eventually fade away.

In your case clearly you did not charge Getty enough. The person used a copy of your image. A picture of a picture. Getty should not make it so easy to do this or they should pay you more.

All that said thanks for the post and for starting a nice discussion.