I read a lot of far left stuff (for work)

Often parts of their analysis of what is wrong with the status quo are not wrong.

But there ALWAYS comes a point where they make a jump, dressed up in a LOT of jargon, designed to hide the reality that their alternative ain't happening

Basically, some form of magical thinking kicks in, whereby they envisage some sudden change in people's views or consciousness, or they hold that some outcome which is manifestly unlikely can be willed into reality by, basically, baseless optimism. It's secular millenarianism

Anarchists are especially entertaining. They want to abolish the state despite rejecting any method that could possibly make that even mildly realistic, for the obvious reason that any such method would corrupt them. This makes their ideology, almost by definition, a dead end

The most honest sort of Marxist are professional Marxist pessimists (e.g Frankfurt School), who have some sort of analysis of why the revolution isn't coming (cultural hegemony etc). They're fatalists. Their politics is basically 'proletariat, I'm very disappointed in you.'

The workers are a constant disappointment to the far left. They have never wanted to be the guinea pigs in that particular historical experiment. So Marxist intellectuals have sought new 'historical subjects' to play the role Marx thought the proletariat would play

Someone like Marcuse is pretty open about this. He thought that students/the peasant masses of the 3rd world etc would play this role.

They haven't proved any more effective and not much more willing, but their failure is seen as less culpable by the far left for some reason