diner (in a restaurant etc) · hanger-on · sponger

If humanity's material life becomes richer year by year, cakes become more and more elaborate, technology becomes more and more convenient, and at the same time, without earlier generations planting trees, later generations would not be able to enjoy their shade, then I am sure that the "rich" life must've been brought about by our industrious forefathers, those who were unafraid to taste the bitterness of hardship.