I just resubmitted this meme - it got "nuked" in the transition to streams. I think - looking at the present moment - that Biden is the new Clinton. And Harris, Bootyjudge, and Warren are the DNC establishment's last hope to stave off the success of Sanders.
The CNN polls that show Biden as a frontrunner might as well be taken in "assisted living" facilities. They literally exclude anyone under 50. So Bernie looks less popular than Biden - and Gabbard is below the margin of error.
The Wall Street donor-base and Clintonian DNC establishment (and their consultants, media surrogates and such) - are terrified of Sanders, and Gabbard... But Bernie is hard to suppress - because of his momentum and visibility from 2016 - thru to the present. But when they're not ignoring Gabbard they're slandering her - or doctoring the video with a distracting blemish, etc.. MSNBC hates them both. This "Blue no matter who" and "unity" stuff seems to cut only in one direction... Meaning you progressives will just HAVE to ignore how we screw you and your candidates - and 'vote blue - for no matter who - we tell you to'.
It turns out that even Republicans would like a reliable healthcare system - with more than half supporting single-payer. The number goes-up to 70% popularity with the general electorate. It's the insurance industry, the party machines and Wall Street that hate that idea the most. Bernie seems to have won-over the audience at his Fox TownHall.
While "centrism", triangulation and picking-off the ever more elusive "moderate voters" - is a strategy that COULD win for Democrats... As Obama showed - the best chances for a Dem win comes from exciting their base, boosting turn-out, and getting young people and unlikely voters to show-up at the polls on election day. Given those dynamics - I think that what you referred to above as "extremes" offer the best scenario for a victory. A large turn-out and and distinct alternative being offered - could even manage to flip the Senate for them - and they need that - because the notorious RBG won't live forever (God bless her, and give her continued strength and health).