Duke Mu, I'm so glad you asked. I bailed on the old ZZL early this year partly to avoid the inevitable angst produced during the toxic election cycle, but I'm rejoining the conversation, albeit in an abbreviated and perhaps brief turn, to pound home my message to Democrats: the Neoliberal Order is over, and, like the other party has (but contrariwise to the Republicans' proto-fascist/state-capitalism model), it's time to develop a new approach.
But nycfan is, as is the custom, mostly right in her assessment: the cake was baked when the DNC picked a woman of color to assume the role of keeper of the (vaguely liberal) status quo. The change from Biden, while undoubtedly an improvement upon what would have been a wipeout, was met in the predictable way: it was the intrinsic 47%-47% political split with the diminished (glass) ceiling represented in the racial/gender hierarchy. Black women still suffer a built-in opposition among even some who might otherwise be of a like mind.
Of course, this was the best Democrats could do, and it mostly worked (rousing the base, creating energy and media attention, raising the funds, etc.) except for the winning part.
But the mistake referenced on your question "Should Harris have continued with her populist message?" should have been corrected after the Hillary debacle.
As Paine keeps reminding us, because the Democrats have had to try to weave together a fractious coalition of the investor/donor class and working classes, management and labor, human rights activists and Zionists, etc., they are in the game of "hide the ball" and misdirection, offering nuanced policies (read: pabulum) to a population that is hungry for red meat: systemic change.
The thing about this situation is that it's an obvious reality that has played out across the Western world in an almost consistent and seemingly inevitable way: the loss of confidence in the center-left and consequent rise of far right nationalism. And none of those members of the center-left coalition has yet to find a landing spot.
Macron tried a technocratic centrist approach, which only landed him in the doghouse with all sides, harking back to our own Clintonism. There seems to be no taste for a wholesale return (in Europe) to social democracy, but we've never tried that here. Unless there is some breakthrough in the zeitgeist (which the looming disaster of Trumpism might offer) or in the political economy, the Dems are stuck on stupid.
As far as the horror of knowing over half of our voters favor authoritarian populism to that center-left pabulum: something always beats nothing. Democrats have to find their something.