Jason Furman is a left-leaning economist who currently works at Harvard but who previously served as chair of the Council of Economic Advisers under President Obama. So his recent takedown of Bidenomics is coming from an ally of the party not an outsider. 

Furman's analysis starts with the fact that voters rejected Biden and Harris because in their view Bidenomics was not a rousing success. If you had to point to a single cause for widespread dissatisfaction with Biden's tenure, it would probably be inflation.

Although there are many explanations for Donald Trump’s victory in the 2024 U.S. presidential election, voters’ views of the U.S. economy may have been decisive. In polling shortly before the election, more than 60 percent of voters in swing states agreed with the idea that the economy was on the wrong track, and even higher numbers registered concern about the cost of living. In exit polls, 75 percent of voters agreed that inflation was a “hardship.”

He goes on to state the obvious, that Biden's economic record over his whole term was mixed at best, and not the unqualified success that Democrats tried to claim it was.

The U.S. economy has bounced back much faster than it did after previous recessions, and its post-pandemic performance has also outpaced that of many peer countries in terms of economic growth. But the recovery has been uneven, frustrated by inflation at least partly induced by the administration’s own policies. Inflation, unemployment, interest rates, and government debt were all higher in 2024 than they were in 2019. From 2019 to 2023, inflation-adjusted household income fell, and the poverty rate rose.

The core problem was inflation, and on this point Furman goes into detail to argue Biden entered office with a plan to spend far more money than was needed at the time.

In 2020, toward the end of the first Trump administration, Congress passed $3.4 trillion in fiscal support; in December, $900 billion was authorized to fund $600 stimulus checks for most American adults. Despite the ravages of the pandemic on public health, many households had never been in better financial shape, with overall debt service payments representing the lowest share of disposable income in decades, delinquencies and defaults remaining low, and record amounts of money sitting in checking accounts across the income spectrum. Economists hoped that as the rollout of vaccines proceeded, so would the economic recovery. In fact, when Biden came to office, the $1.5 trillion of excess savings that Americans had accumulated from the federal largess of 2020 and their suppressed spending was waiting to be unleashed by the reopening—perhaps obviating the macroeconomic need for yet another large stimulus bill...

Against these hopeful prognostications by many mainstream economists, however, the incoming Biden administration moved aggressively, proposing a $1.9 trillion American Rescue Plan even before coming into office. With U.S. GDP three percent below pre-pandemic forecasts as of the fourth quarter of 2020, an additional $650 billion in stimulus—about a third as much—would have been sufficient to fill the hole in the economy.

...economic ideas also played an important role. Policymakers decided to run the economy “hot”: that is, to support high demand to jump-start the economy even if it meant risking higher inflation. The Biden administration believed that the surfeit of demand this would produce would benefit a broad group of workers by increasing their bargaining power and, by extension, raising their inflation-adjusted wages. The administration dismissed dissenting voices who expressed skepticism about this approach, such as the economist Larry Summers, who warned that it would lead to high inflation.

When you add together high inflation and the denial of economic reality the Biden administration engaged in, you get an unappealing combination that doomed Biden and Harris. Furman doesn't even mention Biden's age which was arguably an even bigger drag on Biden in particular, but his argument is effectively that Biden was doomed by his own economic choices, even if he'd been 10 years younger than he was. And that's partly why Kamala Harris, who didn't suffer from the same age problem, still couldn't manage a win.

So why didn't the Biden administration get this at the time? In an interview at Politico about the piece, Furman said he knew economists who shared some of his concerns but who remained silent for fear of being attacked as traitors to the cause.

There is, in general, too much inhibition in people’s conversations about economic policy. There were a lot more critics of the size of the American Rescue Plan privately than there were publicly, and same thing on student loans. I knew many economists that thought it was terrible what was happening on student loan relief, but they were afraid to be yelled at on Twitter, or didn’t have a platform, or didn’t want to risk a future job in a Democratic administration. And so, people get a mistaken impression of what it is that economists think on any given topic because there is so much self-censorship.

Now, I have the luxurious position of a secure job at Harvard, and I had a great government job in the past, and I’m not trying to pursue my next government job. So in some ways, it’s easier for me to do this.

In other words, no one wanted to speak the truth about some of Biden's economic plans for the same reason no one wanted to speak the truth about his age. There was no upside to bucking the party and plenty of potential upside to keeping their views to themselves. In some sense, the Biden administration became a victim of it's own success at silencing critics. Because while the critics held back their real views in many cases, the voters ultimately did not.