If you accept that he was voted in to 'shift the debate' to a more left-wing Labour party, and ultimately, Westminster, then he was only going to do that by creating a coherent message that people wanted to hear, and spreading that message to the British people. He's utterly, utterly failed on that front, with Labour not doing anything to 'sell' their message to voters - you can see it in the referendum and Scottish and local elections, or you can see it on the news, where we see the Tories repeatedly getting away with selling their own lies on a whole host of matters. I don't see how anyone can have seen Jeremy's work as leader of the party and believe he and his team are capable of building an effective opposition.
And Momentum have 'demonised' their own enemies just as much, the deselection threats are more reminiscent of the Tea Party than anything else we've seen in British Politics.