Some people are upset I said that Marxist economics (which I am differentiating from communism) wasn't really viable in economics by Keynes's time.
I want to impress upon people that this of course doesn't mean Marxist economics wasn't talked about by any serious economist ever. That's obviously not true. You all listed many of them - to that I'd add Paul Sweezy and Ronald Meek, who I don't remember seeing in your list.
OK, so? If the question was "did anyone at all take Marxist economics seriously in the twentieth century" then I would have a different answer. But the question was whether there was a great debate between Marxists and New Classicals or Marxists and Keynesians and the answer is that there wasn't (I assume no one disagrees with me on that), and part of the reason was there weren't a whole lot of credible Marxists to argue with.
The Cambrdige Capital Controversy may have discussed a lot of Marx, which wouldn't be surprising to me at all given some of its participants. But even that is obscure to most economists. The SCD is the next closest thing but as I said that really deals with state socialism not Marxist economics.