I think there is some truth in this phrase and it relates to the value of money. Someone working hard for their wealth is not only responsible with their money, but they strive to give their children what they did not have such the opportunity for an education. I child with wealthy parents has potential to be "spoiled" and may not equate money with hard work.
The phrase can also reflect the different economic conditions for each generation. People in their 70's today are grandparents and performed more physical work to earn their living. People in their' 50's are fathers and were more educated, accessing professions within business, law and other white collar positions. The economy during their employment boomed. People in their 20's and 30's now are struggling financially because they did not have a "nest egg" prior to working and all the cultural rules and norms that applied to past generations' success do not apply anymore. Education is now the #1 source of debt instead of employability.
I wonder what we will say about the next generation- rich grandfather, poor father, and ___ son?