@blatham,
Interesting observations, and I suspect those with respect to Biden and Sanders are largely correct. However Do you (or perhaps the author) believe Booker, Harris,Buttwhatever O'Rourke, or any of the other candidates are themselves ready?
Of all the candidates I suspect Kamila Harris is probably the now most likely to succeed in the primary contest. She is smart; checks most of the boxes in the contemporary favored groups ranking; has so far evaded potentially fatal gaffes, and appears to be a canny politician. I met her once, about a decade ago, in a large group in a San Francisco Restaurant at an event featuring Willie Brown: she was his then current girlfriend, and a rising new face in California politics.
The apparent self-absorption of Democrats (Harris included), and their political commentators looks to me like a serious and possible fatal weakness, not unlike what did them in in 2016. They have a very serious struggle ahead in putting together a winning party platform, given the recent lurch to the left that has emerged among them. The "Green New Deal" and various promises being recited by the candidates haven't made that any easier. The public appears to view party platforms as real precursors to action a good deal more than a decade ago, and fashioning one that satisfies both the new left and the independent voters who make the difference is likely to be very challenging.
So far the Democrat candidates appear to themselves by among the principal consumers of a new wave of left wing political propaganda, and history suggests that is can lead to dangerous (for them) illusions.
However, even here I think Harris may have an advantage, She has, in her California political career, demonstrated agility and a Chameleon -like ability to appear to satisfy contradictory political waves and trends.
However I find the prospect of her presidency to be an awful thing, and happily, very unlikely.