Rags to rags in three generations

Possible interpretation: The first generation in a family makes money (goes from rags to riches); the second generation holds or keeps the money; and the third generation squanders or loses the money (and so goes back to rags).

Note: rags (noun) = old, tattered clothes | generation (noun) = all of the people born and living at about the same time; a set of members of a family born and living at about the same time