But the right aren't complaining about being taken over and constantly bellyaching about how everything is against them. I'd just leave them, start a new party. As you say, politics and society has changed. Start a party to meet that need. Surprised Corbyn hasn't tbf.Why don't the right do that? It was tried before with Williams and Jenkins, remember? That's why I see them as parasites.
Personally, I think the reason the left don't leave is because they probably know the unions won't follow. Ultimately the unions want influence and to influence power. Going all in with Monmentum and the ilk destroys any chance of that.
Faustian pacts all round.