From shirtsleeves to shirtsleeves is only three generations meaning

HOME PROVERBS

family

From shirtsleeves to shirtsleeves is only three generations

suggests that:
A family may pass from poverty to wealth and back to poverty in 3 generations; The first generation become rich with their children learning from their parents and run the business well, but the third generation often get spoiled and idle and ruin the business.
also
From clogs to clogs is only three generations.