The past few weeks, particularly since the debate, I have been collecting a largely anecdotal and entirely unscientific sample of opinions and reactions of Democrats. Part of it comes from conversations with a group of acquaintances that is at least geographically diverse, including Georgia, Arkansas, LA, the bay area, and Washington state. Some of it comes from exchanges on social media. Some from professional observers like Josh Marshall and Charles Pierce who have proven themselves clear eyed in the past.
Here's an overview of what I heard.
Take this with however many grains of salt you find appropriate, but I am reasonably confident that these opinions and general mindset give a pretty good picture of where the Democratic Party is at the moment. The consistency of what I'm hearing is remarkable. People I talked to kept telling me the same things, and it is a consensus sharply at odds with what pundits at places like the New York Times are telling us we should be hearing.
Biden's age was always a concern for these people, but not in the way that Nate Silver or the New York Times editorial board would have you believe. There was relatively little concern about his ability to do his job, partially because of how well he had been doing it up to now and partially because we had faith in him and in the people around him to do the right thing should the time come. Everyone I talked to had long accepted the possibility that he might step down sometime during his second administration.
The worry was that, while Biden's age might not affect his performance as president, it could very much affect his performance as a candidate. Being head of state does not require the energy level of a game show host, but increasingly political elections do. This was especially a concern when running against Trump, a politician whose persona was equal parts professional wrestling heel, sideshow barker, and second-tier Vegas insult comic. Trump's energy levels vary dramatically (how many defendants sleep during their criminal trials?), but being a narcissist, he fed off of the energy and adoration of the crowds. As long as he was the center of attention, he would seldom come off as a tired, old man.
This worry was elevated to genuine fear when Democrats realized that most of the establishment press was doing its best to bury stories about Trump's physical and cognitive decline, and there was a lot to bury. Slurred and garbled words. Glitches. Calling people by other people's names, often for extended periods. Weird digressions. Memory lapses. The previously noted inappropriate naps. A campaign schedule that consisted mainly of days off. 
Unlike with Biden, Democrats noticed that stories of Trump's cognitive decline had remarkably short half-lives outside of liberal outlets like the New Republic. Case in point:
“I spoke to a number of CEOs who I would say walked into the meeting being Trump supporter-ish, or thinking that they might be leaning that direction,” said CNBC’s Ross Sorkin. “[CEOs] said that he was remarkably meandering, could not keep a straight thought, was all over the map.”
Trump promised the CEOs to cut taxes and bring the federal corporate tax rate down from 21 percent to 20 percent, a lackluster attempt to elicit excitement from the suits. One attendee summarized Trump’s message as, “We’re going to give you more of the same for the next four years,” according to CNBC.
“These were people who, I think, might have been actually predisposed to him,” said Sorkin. “And [they] actually walked out of the room less predisposed to him, actually predisposed to thinking ‘This is not necessarily—’ as one person said, ‘this may not be any different or better than a Biden thought, if you’re thinking that way.’”
Here's how it was covered in the New York Times by their A-Team, Jonathan Swan, Maggie Haberman and Charlie Savage.
Former President Donald J. Trump told a group of America’s most powerful chief executives on Thursday that he intended to cut the corporate tax rate to 20 percent from 21 percent, according to three people who attended the meeting and who spoke on the condition of anonymity because the ground rules stipulated the meeting was off the record.
Mr. Trump made the remarks from a comfortable gray armchair during a conversation with his former economic adviser Larry Kudlow in front of the audience of dozens of leading chief executives, including Tim Cook of Apple, Jamie Dimon of JPMorgan Chase, Doug McMillon of Walmart and Charles W. Scharf of Wells Fargo.
They had gathered on Thursday morning in Washington for a meeting of the Business Roundtable, an influential corporate group, and there was said to be palpable relief in the room when Mr. Trump, who has been trying to woo business leaders as potential donors, told the executives much of what they had hoped to hear.
...
Mr. Trump, whose public speeches are often characterized by conspiratorial promises to root “Communists” out of government and hard-line policies such as overseeing the largest deportation operation in American history, was described by one of the people who attended the meeting to have sounded relatively more measured than usual, modulating his messages for the elite audience. He most strikingly softened his language about immigration.
But it was his spiel about taxes that seemed most visibly pleasing to the executives in the room, according to people who attended the meeting.
The realization set in that while both candidates were clearly not the men they had been four or eight years ago, the press was only interested in the Democratic side of that story. Under these conditions, having a candidate who lacked the stamina and energy to successfully campaign was, for lack of a better word, scary.
And yet, no one I talked to had been eager to see Biden step down. Nate Silver and various writers at the New York Times, Politico, etc. complained loudly about the irrationality of Democrats wanting to stick with Joe. There actually was a rational explanation for the seeming contradiction but it was not one that Silver and company would have cared for. Democrats were afraid that people would listen to the New York Times.
One thing that has really jumped out at me watching recent events is how much the Democrats of 2024 yearn for unity and how angry they get at anything that threatens that unity. The concerns over the Biden campaign, though substantial, were still less than the concerns over the chaos that might ensue if he stepped down. The process being aggressively lobbied for by people like Ezra Klein or Ross Douthat seemed likely to result in a bitterly divided Democratic Party that would be crushed by Trump and the MAGA Republicans up and down the ticket. If you could have convinced these Democrats that the new nominee would be Kamala Harris, someone they had voted for explicitly in 2020 and implicitly in 2024 and whom they considered the legitimate successor, you would've run into far less resistance, and if you could also convince them that the party would come out of the transition far more unified, you would've seen almost unanimous support.
One last point. This is, at least for the moment, a happy and hopeful group.
