Social mobility

Social mobility's only real meaning is the ability to move up socially. It only talks about one direction of movement - upwards. Not downwards, or even sideways. People do not want to move down social scale so it is implied that efforts to promote "social mobility" always create win-win, unlike a zero-sum game. However, social mobility is directly linked and contributed mainly by economic power, either on the mobilized's part or mobilizee's. If economic gain is not zero-sum, is it possible that social mobility is indeed a win-lose game also? As many move upwards, there are always those moving downwards or left behind. Or is it simply that the bar gets continually raised until everyone is royalties? Five-starred becomes six, seven or ten-starred. Luxury becomes standard and first class becomes economy. Is the aim of social mobility Utopia?