Marx argues that societies will move from pre-capitalism (e

Marx argues that societies will move from pre-capitalism (e.g. feudalism) to capitalism, socialism, and, eventually, communism. Why have some countries moved in the opposite direction (from socialism or communism back toward capitalism)?  
To what extent can one effectively espouse ideas about radical social change while benefiting from economic privilege? (Was there any inherent disconnect between Marx living an initially upper class life and his written concerns for the working poor? Was his advocacy more effective when he was poor himself?)
As we have moved to a more service-based economy, has alienation decreased or increased and how/why?