The fact that you even invoked the term "mainstream left" here makes it perfectly clear that you're more than happy playing identity politics. You speak in terms of political labels, not in terms of mechanisms for solving problems.
Why? The greatest mind in the world might solve poverty tomorrow but unless they can convince the public they may as well keep it to themselves. Let's also not forget that professional thinkers are often incorrect and disconnected from reality. Support for communism was quite high amongst professional thinkers. Not to mention that professional thinkers these days includes the like of feminist studies professors that are about as regressive as they come.
So, yeah. Let's forget that. Because it's juvenile and petty.
PS: You're talking to a feminist and communist. I'm not sure why you'd imagine I'd object as you do to the points you raise. I doubt you've ever read any communist or feminist literature, or that you'd care enough to understand it if you did.
Your the intellectual elitists that Trump voters (and myself) hate. You're influence on the left is why they are losing elections and why there are very few left wing parties I would vote for these days.
But whatever. You're petty and can't avoid identity politics. And I would rather talk about actually relevant ideas, so have a good life.
Not sure exactly what you're talking about but I've long been a proponent of UBI for instance. But new ideas like this aren't being adopting by the mainstream left and probably won't for some time. You never get any progress without a firebrand to sell the message. The mainstream left seems more interested in playing identity politics as a wedge than coming out with a positive action plan.