Booker: I suspect Booker is going to be pulling the "Newt Gingrich". The only reason Newt ever ran for President, was in hopes that the person who actually won the nomination would pick him as a Vice Presidential candidate, or offer them some kind of cabinet position.
Harris: Her position on gun control throughout both her political and legal careers will make her a complete non-starter in the South, Midwest, and Rust Belt.
Warren: Elizabeth Warren is a proven plagiarist who profited from her plagiarism. She directly stole two recipes that she published in the collaborative cook book "Pow Wow Chow". The Democrats may want to try someone who isn't a documented and proven liar.
Bernie: Bernie had a real chance back in 2016. His endorsement of Hillary destroyed his chances in 2020. Republicans will be able to take the footage of Bernie endorsing Hillary Clinton, and be able to turn Hillary Clinton into an election issue for 2020. Due to the fact that he's an outright socialist, States like Virginia would flip back red.
Biden. Another guy who had a real shot back in 2016. Unfortunately for him, due to family issues his head wouldn't have been in the game. Now that people have seen that life under President Trump isn't going to result in Chicken Little "the sky is falling" scenarios, Biden and the Democrats won't be able to sell the idea that now President Trump is somehow uniquely dangerous like they tried in 2016.
I've predicted it in other threads, and I'll predicted here:
President Trump will leave office on January 20th 2025.