A few thoughts:
(1) Biden is going to be the nominee, barring a real health crisis (Which of course can’t be ruled out at his age, especially with the death flu and all. I think it’s certifiable to nominate people who would spend most of their presidency in their 80s, but clearly few voters see things that way).
(2) Sanders’s strategy was to win a third of the primary vote, on the assumption that the rest of the field would remain sufficiently fractured to make this a winning strategy. This isn’t speculative or hyperbole: this is what the campaign was saying a year ago.
As somebody said in comments (come forward and claim your prize) you can be a party leader or a gadfly, but you can’t be both. He tried to be both, or maybe the leopard can’t change his spots, to coin a phrase.
(3) Elizabeth Warren’s biggest problem was that she’s a woman. The exact same qualities that made Barack Obama so attractive — super smart Harvard Law product with a folksy common touch — were the very things that made her unattractive to voters. (The intelligence was off-putting, the folksiness was somehow fake, Harvard is elitist!). Why the difference? Because she’s a woman, and not the wife a very popular ex-president. Sure she made mistakes, unlike the perfect campaigns run by Joe “I Personally Broke Nelson Mandela Out of Prison” Biden and Bernie “Viva Fidel” Sanders, but in the end the problem was her gender, because misogyny.
(4) The best thing about last night is that Mike Bloomberg spent $18 million in Virginia while Biden spent $300K, and Biden just killed him. Money is important, sure, but you still can’t just buy a nomination, let alone the presidency.
(5) I’ve been extremely negative about Biden relative to the other choices in the original Democratic field, but he is of course infinitely preferable to Trump on every single metric, and he would probably do an OK job as a caretaker president, assuming his health, and especially his mind, hold up for four years. BTW people who assume he won’t run for a second term are making a huge and unwarranted assumption. I would be surprised if he didn’t run, assuming no really serious health issues arise. I mean that’s just how people are, especially people who become president. This could lead to a messy situation four years from now, to put it mildly.
At this point, doing everything possible to make sure we have to deal with that problem four years from now is job #1 for every Democrat, democratic socialist, actual rather than fake Never Trumper, and essentially anybody who isn’t a an authoritarian-worshiping ethno-nationalist. Gotta get down to it.