Yes, the Dems can be faulted for their weak bench, but in electoral terms, their biggest weakness is in fifty-year-olds, not thirty-year-olds. Why isn't Tim Ryan running for President. Why is there no Barack Obama of 2008?
Does the party really not want white male votes? Three nights of convention, all hosted by (excellent, but so what?) women of color. Where are the autoworkers and coal miners? Their jobs are obsolescing, but someone needs to talk about THEIR next act, not pretend they don't exist. LGBTQ interests should be served, but not "centered" more than "ordinary" workers.
Biden made a tactical mistake by committing himself to naming a woman Veep. How can he promote her as the best PERSON when he has already disqualified half the human race? There are plenty of adequate white male applicants for all the important positions in our society, yet no one credibly uses that fact as an excuse for choosing only from that pool. I am not saying that Biden should have chosen a white man, just that he should not have denied himself the opportunity to say his pick beat out EVERYONE ELSE, not just the other women of color.
Identity politics cost HRC the election. The party has nominated an old man for President, but it's still more concerned with the VP candidate's demography than her biography or philosophy.