Yes, but in Marxism it is essential, so fundamental that it is the last thing to go. The basic idea is: what one capitalist gains, another loses (hence Marx' forecast of growing, and finally universal, oligopoly and monopoly); what the capitalist class gains, the lower classes lose. The point has to be emphasized, because it has to overcome a common attitude among lower classes, that is that their prosperity and safety is tied up with the success of their upper-class leaders (hence the loyalty to kings and the like which is so widespread a historical phenomenon).