Is Piketty a socialist? I'm 90% sure he opens Capital in the a Twenty first Century with the claim that because the advanced capitalist states haven't yet had a revolution, Marx was wrong. It's to be expected of a French public intellectual, I suppose, but this demonstrates a severe misunderstanding of Marx(ism). His book is still worth reading.
Wolff is great. His analysis is often spot on. His 'solutions' can be very liberal but I think he's trying to bridge a gap and shift the narrative. I think he's a lot more radical than he sometimes appears. He knows that if he can find a way of appearing 'reasonable', he can get people to be open to the facts and narrative he's sharing. And if people accept those facts and that narrative, they will eventually be amenable to Marxism. The co-op thing is by-the-by; Marxism leads all honest people to revolutionary thought.