//That can never happen//
Then expect society to fall apart. Because we need to figure out some way to make unemployment productive or not socially damaging - which the current system cannot easily cope with.
It's probably worth stressing that this is already starting to happen. My husband works at an international company where the most advanced new factories need only 15 people to run; in warehousing, storage, law, and finance, machines are already displacing humans on a significant scale. It's only a matter of time before robots are a sufficient improvement on human drivers (who are rather crap) and start replacing them in transport.
Ignoring this problem is not going to make it go away. We need to find some way to adapt, because at the moment there isn't an obvious alternative to the system we've got.
Oh and Corbyn's solution is vapid rubbish. It does not matter who owns the machines - they are still going to replace people, and that's the crux of the problem.