Let’s take a look to Bernie at 1979……..
https://pbs.twimg.com/media/ERW9qKIXkAAcPRD?format=jpg&name=medium

https://twitter.com/ChiefSteveGeorg/status/1231098609493520384?s=20

https://www.npr.org/2017/08/24/545812242/1-in-10-sanders-primary-voters-ended-up-supporting-trump-survey-finds

A more important caveat, perhaps, is that other statistics suggest that this level of “defection” isn’t all that out of the ordinary. Believing that all those Sanders voters somehow should have been expected to not vote for Trump may be to misunderstand how primary voters behave.

For example, Schaffner tells NPR that around 12 percent of Republican primary voters (including 34 percent of Ohio Gov. John Kasich voters and 11 percent of Florida Sen. Marco Rubio voters) ended up voting for Clinton. And according to one 2008 study, around 25 percent of Clinton primary voters in that election ended up voting for Sen. John McCain, R-Ariz., in the general. (In addition, the data showed 13 percent of McCain primary voters ended up voting for Obama, and 9 percent of Obama voters ended up voting for McCain — perhaps signaling something that swayed voters between primaries and the general election, or some amount of error in the data, or both.)

All of that said, one other figure that stuck out to Schaffner: Compared with those numbers above, Clinton 2016 voters were remarkably loyal — “I found basically no Clinton primary voters who voted for Trump,” he told NPR in an email.

The DNC basically chose the overwhelmingly weaker nominee (and sometimes they even did it blatantly), and so they lost to Trump instead of to have their billionaire donors lose to Sanders and to the American public by Sanders becoming the nominee and then the President. Keeping the support from their billionaire donors was the DNC’s top priority, in 2016. Of course, America’s voting public generally don’t know that both the DNC and the RNC are far more committed to keeping the support from their billionaire donors than they are committed to winning elections. This is why those voters pay close heed to what their Party’s leaders say about which candidates are ‘electable’ and which ones aren’t.

The voters don’t understand how politics actually works, in today’s America — they think that winning the current general election is a Party official’s top priority. They think that Party professionals are professionals at selecting winners, but instead Party professionals are professionals at pleasing their Party’s billionaires. If a voter wants to please him or her self instead of please a group of billionaires, that voter ought to vote for whomever that voter thinks would best serve that voter and not serve any group of billionaires

As the Huffington Post reported on March 4th, the day after Joe Biden’s huge Super-Tuesday win, “‘Voters liked both candidates but clearly consolidated around the one they saw as most electable,’ said Jared Leopold, who was the communications director for the Democratic Governors’ Association during the race. ‘The intraparty ideological fight pales in comparison to the thirst to beat Donald Trump and his buddies.’”

Those people’s top concern is to please the few individuals who fund their careers. Winning the current electoral contest isn’t actually their #1 concern, though voters think it is. The Party professionals have a longer-term, personally career-oriented, goal in mind — pleasing their bosses’ bosses.

It wasn’t Warren’s gender that turned off Democrat donors — it was her agenda.
Sanders is just as toxic to them. They don’t have him feeding out of the usual troughs (his are somewhat more esoteric).

The non-presidential elections are far more important, because that’s where the “rubber hist the road” – donor priorities are legislated and enforced. To some extent, the President really is a quasi-figurehead; although the office still has a great deal of nominal power, it can only be expressed through influencing lawmaking, or directing enforcement (or not) of existing laws.

After 1815, there were two major episodes of domestic political violence. Both were in Paris, not in the rest of the country. The first (in 1848) had a four digit death toll and the second (in 1871) had a low-end-of-five digit death toll.

FWIW, just came across a post that actually includes statistics that answer the question:
https://www.zerohedge.com/political/joe-biden-2020-duplicates-hillary-clinton-2016
(H/T Zero Hedge blog)

…which quotes this post:
https://www.npr.org/2017/08/24/545812242/1-in-10-sanders-primary-voters-ended-up-supporting-trump-survey-finds

in:

This is not to say that it’ll happen again if (or rather, “when”) Sanders is passed over in favor of Biden.

The answer ultimately depends on to what extent the berserk, non-stop demonization of Donald Trump will have galvanized even the “They-betrayed-us-once-again” minions of the Marxist manipulator to eject Trump from the Oval Office.

Whatever happens, it won’t be pretty.

https://www.washingtontimes.com/news/2020/mar/6/bernie-sanders-youths-abandoned-him-bong/

At the moment it doesn’t even look like they’re voting for him…so I’m not sure they’ll just run right out and vote for Gropey Joe…or anyone else for the matter.

I don’t have any hard data on the “bong” but I’m pretty sure it ain’t running for President. 😉

Trump asks an important question about Biden
https://uploads.disquscdn.com/images/f04e749cd59eacb26d4d9a30f03e3f27937b66dc0875fb15569c5088d27991cf.jpg

Bernie-opoly.
https://uploads.disquscdn.com/images/055cf2f77cbb8cdd21db710306091f76543bc94d158ef76d138e967ab9d5ecd2.jpg

Which is really funny, because the original game actually was supposed to be a critique of capitalism.

How in the heck did Joe Biden’s mummified campaign come back to life? Or is it just back to zombie status—still dead, but up and moving and menacing the living? … Our conclusion is that Democrats decided they are more the party of creeping socialism than Bernie socialism, in which case it is better to have an actual creep as the nominee.