Currently Warren is making all the wrong moves. More or less a social democrat, the fact is the US people are not social democrats, let alone communists, which is exactly what she will be painted into a corner by. Currently, I do not anticipate Warren to win the presidency. Whether she wins the Democratic nomination is still an open question.
Meanwhile, Biden still dreams of being a gerentocrat. In this election we are going to see millenials rejecting the gerontocracy. I do not expect Biden to win the presidency. He might not even win the democratic nomination.
All the other contenders for the democratic nomination are sufficiently young and “unknown quantities” to be capable of being nominated and elected. They have all the mistakes to make. Warren and Biden have probably both made sufficient mistakes to lose either the nomination or the election or both.