"By this point in the 2016 Democratic primary, in contrast, a huge bloc Democratic governors, senators and representatives had chosen a candidate, Hillary Clinton."

"But this cycle, the overwhelming majority of congressional Democrats and Democratic governors are still on the sidelines. Indeed, the 2020 Democratic primary looks more like the 2016 Republican primary, when most GOP officials held their fire until deep into the race, than that year’s Democratic race.... Warren has two obvious problems with party elites. First, there is the perception among some of them that her left-wing stands, such as Medicare for All, are too risky for the general election and decrease the party’s chances of defeating President Trump.... Secondly, electoral considerations aside, there is a center-left wing of the Democratic Party that fundamentally disagrees with Warren’s more leftward positions... Warren also has a third challenge with party elites that is less obvious. The Massachusetts senator clashed with senior aides to President Obama for much of his tenure in the White House. She, like Sanders, isn’t quite in line with the party’s establishment. A Warren administration would probably be less likely to hire former Clinton (Bill and Hillary) and Obama aides in key posts than, say, a Biden, Booker or Harris one. So people connected with the party establishment (like many DNC members) may be fine with Warren but prefer other candidates for more self-interested reasons.... The potential danger for the Massachusetts senator is that 'party elites lukewarm about Warren' turns into 'party elites organize to stop Warren.' And perhaps Democratic voters care more about the views of their party’s elites than Republican voters did in 2016."

From "Why Aren’t More Democrats Endorsing Warren?" (FiveThirtyEight).

I wish there were some discussion of the way Democratic Party elites behaved in 2008, endorsing Hillary Clinton early and interfering with the rise of Barack Obama. Aren't they avoiding giving Biden what they gave Hillary in '08?

Anyway, things were different then. There were "superdelegates," and the elite had reason to think they could control things. Here's a WaPo article from September 2018, "The DNC voted to strip superdelegates of their powers. Will it matter for 2020?":

Since the mid-19th century, both parties have selected their presidential candidates at national conventions. At these conventions, delegates from each state vote to select the party’s presidential and vice presidential candidates. Originally, these state delegates were appointed by local party leaders. But starting in 1912, a number of states began to organize primaries or caucuses that allowed voters to select which candidate their delegates would support.

The number of primary states dramatically expanded after contentious conventions in 1968. Since the 1970s, all states have relied on primaries or caucuses to divide up their delegates. But Democratic Party leaders very quickly grew concerned about which candidates their primary voters were selecting. In 1972, George McGovern won the Democratic nomination — and in the general election, lost in a landslide to Richard Nixon. In 1976, Jimmy Carter — a political outsider — won the Democratic nomination and the general election, but alienated many congressional Democrats and much of the public while in the White House. In 1980, he lost in a landslide to Ronald Reagan.

After Carter’s 1980 loss, frustrated Democratic leaders wanted to regain influence in picking the nominee. A DNC committee proposed adding “superdelegates,” spots given to party leaders who were free to vote for whatever candidate they thought would be most competitive. Since 1984, between 14 and 20 percent of the total delegates at Democratic conventions have been superdelegates. In 2016, these superdelegates were predominantly DNC members and elected officials.

The superdelegate system became particularly controversial during the 2016 presidential primary fight between Clinton and Sanders (I-Vt.). During those primaries, Sanders supporters attacked the DNC — ostensibly a neutral arbiter for all factions of the party — for purportedly supporting Clinton. Sanders supporters also criticized the primaries’ structure — including the superdelegates — as unfair to Sanders.

In response, the DNC has adjusted how it selects its presidential nominee. Earlier this summer, a DNC subcommittee voted to make it impossible for superdelegates to have the deciding vote on the first ballot at a national convention. In practical terms this means that superdelegates cannot vote in the first voting round if their support is going to decide the selection. If no candidate wins a majority in the first round, superdelegates get to vote in subsequent rounds. Thanks to DNC Chair Tom Perez — who lobbied heavily for the change — the DNC has now voted to implement the proposal....

Between 1984 and 2016, in every case the candidate who won the most pledged delegates through primaries and caucuses was also supported by a majority of superdelegates. For example, in 2008 and 2016 the delegate race was incredibly close... But while superdelegates’ votes haven’t directly changed who won the nomination, they may matter in indirect ways. Superdelegates often announce who they’re supporting well before the convention. Candidates have in the past spent a lot of time and resources on trying to win their support.

So the new system may change the 2020 primaries after all. Candidates will now be relieved of having to woo superdelegates. They are still likely to care about getting party leaders’ endorsements. But they do not have to ensure that they get and keep superdelegates’ votes.lll

All that means we’re not looking at a radical change in the race for the next Democratic presidential nomination. But Democrats can be assured that the process will be slightly more democratic, in the sense that ordinary voters — and not party elites — will have the final say. What’s more, party leaders may have a little less influence, with less ability to anoint a candidate before the first primary. Meanwhile, the DNC hopes that this relatively minor change will help restore the confidence of voters who thought the 2016 primaries were unfair.

It seems as though that FiveThirtyEight article ought to have factored in the change in the superdelegates, but I see that the entire website hasn't mentioned superdelegates once in the last month. It seems to me that if the elite — the superdelegates — still thought they could control things, they'd have backed Biden already. They gave up control and now they don't know how to handle it. Just a hypothesis.