What I Don't Understand About Crop Insurance

This quote:

For quite a few years, GRIP has had a good grip on many farmers.  It is a crop insurance policy that is easy to deal with, and it usually pays, despite how good of a crop you had.  GRIP is the Group Risk Income Policy that is based on county averages, and if calculated revenue was below the projection at the early part of the year, GRIP policy holders would get an indemnity check.

What I don't understand--how can an insurance company make a profit on a policy which "usually pays off".