Those suggesting capitalism is in its final throes assume two things: 1) Economic inequality equals injustice; 2) The existence of economic inequality means that capitalism must be replaced. Neither proposition is true.
Is capitalism perfect? Of course not. But free market capitalism has brought more prosperity to more people than any other system conceived by man. Poverty may be a problem but economic inequality itself is not. Economic inequality can exist for a variety of reasons, one of which includes some people working harder than others. While everyone should have equal opportunity as much as possible, equal opportunity does not, can not, and will never mean equal outcomes.