Corbyn and McDonnell were too open about their policies to succeed, nobody actually wants Marxism. Labour are successful when they have a slick leader who dresses up all the horrors as good things, and changes the language so that we cannot think properly or mention the horrors. This was Tony Blair.
Labours aims remain the same... state control of everything, no individual freedom, no private businesses, everybody working for the state. No national boundaries and no private property, so everything belongs to the state. If you don't like working for the state the state will replace you, in your house, with someone from overseas. No morality or Christianity. All power relies on force, no more democracy. All drugs to be legal. All criminals go free, the only people punished are those who oppose the state.