The “lost” enthusiasm resulted from the Democrats in Congress being unenthusiastic with the ACA they just passed and their half-assed response to the 2008 financial collapse. Since Biden was the White House’s point man for Congress, I think he deserves a good part of the responsibility of the 2009-2010 debacle. And as for disappointments with his fingerprints on it, there’ve been sooo many others. Waiting for his apology for putting Clarence Thomas on the SCOTUS bench.
My disdain for the corporate Dem and BS artist supreme notwithstanding, of course I’d vote Biden over Trump. I mean, no brainer there.