I think his current poll numbers are a bubble. He has name recognition so I think many people polled say Biden just so they don’t feel ashamed of being “undecided”. Just some loose speculation there.
He seems to be taking the H Clinton campaign approach of avoiding rallies and just meeting with donors or giving speeches to organizations (rather than campaign rallies). Imo that’s either total hubris or his campaign knows that staying aloof preserves his poll numbers but having to make political statements will just hurt him.
So I don’t think he’ll get the nom. But if he did, Trump would win because Trump’s smaller base is more motivated whereas Biden was to the right of Obama and won’t be able to pull that kind of enthusiasm (with a base that was disappointed in Obama’s moderation and have moved further left since then.)
In a match up with Trump, what would Biden’s counter-argument be: “let’s return to a time of civility in politics and reaching across the isle. We might not agree on everything, but I’m a reasonable fella, we can work it out”?
...not exactly storming the barricades type stuff compared to Trump’s inevitable campaign Armageddon-talk about defending the US from “invading hordes” and caravans of scary “others” coming to take your stuff.