the.com/diminishing returns

means A point in any activity where each extra unit of effort, time, or resource yields less benefit than the one before it.

from Born in economics, specifically the 'law of diminishing marginal returns,' a principle classical economists worked out studying agriculture — pile on more labor or fertilizer to a fixed plot of land, and each additional input adds less and less extra yield, since the land itself can't expand to match. Economists like the Physiocrats and later Ricardo and Malthus wrestled with versions of this idea in the 18th and 19th centuries, mostly puzzling over farm output and population growth. The phrase eventually escaped the textbooks and walked into everyday speech, where it now describes everything from pizza slices to overtime hours.