Capitalism can't last forever.Social systems are mortal.Like the human beings who compose them, they are born, mature, decline, and eventually die.The history of capitalist society shows it is no exception. It too has moved from birth through maturity to decline, and is now approaching death.
It might not die in its entirety, like most isms and believes some ancient ones are still being kept alive by small groups of people. But eventualy a new form of ism will evolve and take over. Probably led by science, like bitcoin came and slowly is evolving the financial world as we now it. Bit too slow, but hey, I can wait!