Biden never got above low single digits among Democrats the other times he ran. Now he is the run-a-way nominee among a large and somewhat talented Democratic field. The only question is has Biden gotten smarter or have the Democrats gotten dumber.
the DNC and their media have become more and more corrupt, and Joe/Jane voter has become stupider and stupider, and the non idiots capable of thinking on their own have no credible option, as are far out numbered by the idiots and sheep.
Joe wasn't doing well this primary either, till MSNBC, CNN, and the DNC social media army, told the idiot sheep the Pubs would win every seat in every contest if communist socialist Bernie were the nominee, and that Bernie would to turn the US into the worst of Russia and Venezuela after replacing Washington's portrait in the White House with Castro's..
this wasn't Fox News pushing this all day every day once things looked bad for Biden, it was MSNBC and CNN and the DNC social media army, doing it.
then the DNC threatened James Clyburn with taking away his majority whip title if he didn't endorse Biden, and Clyburn cared more about his leadership position than he did about about his constituency having accesses to healthcare or higher education. (and neither Clyburn nor Nancy got their leadership positions to begin with without being owned by big money, who controls those positions).
then the DNC held a gun to Klobuchar's, Pete Butt's, and Stoyer's heads, and told them they'd Bernie them too if they didn't drop out the night before super Tues and endorse Biden.
party guns to the heads of politicians matter, even if said politicians were politically more aligned with Bernie, and nobody in history drops out the night before super Tuesday, totally f'ing all their volunteers and staff and supporters up the back side, not to mention their own policies and ambitions, absent a loaded gun to their head.
the DNC money and media base was never going to allow anyone but Biden, any more than they were anyone but Hilary in 16. (which is how we got Trump in office now).