Because without it he has no chance of implementing his revolution. I don't mean wealth distribution and the resurrection of public services. His revolution's aim is to prove capitalism and free trade doesn't work....
2. companies (especially in the UK) could grow by adding cheap labour rather than increase productivity with investment. This led to massive increases in part time, self employed and zero hours contracts, and ultimately the gig economy.
Similarly Corbyn doesn't actually want poverty to go away. In fact he needs it to remain. It might even be better for it to increase quite a bit more. The angrier the base the more support he gets.
Why does this have no traction with Corbyn? Could it be it's because:
1. Since he is a populist, economic failure increases his base's anger, disenchantment, this increasing support for him
2. The only way into power for a revolutionary is via crisis
3. He proves capitalism doesn't work by engineering the very edge case circumstances when it produces adverse outcomes for all but about 500 people (disaster capitalists).
... When it can, obviously.
Brexit provides the crisis by which the revolutionary populist can rise to power. There's no other feasible circumstances for such a dim, inept leader to take power.
/Ends