Biden repeatedly claimed "I am the Democratic party" when he was nabbing the candidacy from Bernie and Buttigieg and the dozens of other democratic primary runners.
Now suddenly there is an insurmountable obstacle blocking his agenda in the form of two Democratic Senators? There's no way Senators should have sway over the President, particularly when they're of the same party.
These obstacles are illusory and just provide a convenient cover for Biden to hide behind. I would agree his presidency is dead in that he's lost all authority over the policy that's passed. At this point, even though it's shockingly early in his presidency, he's contributing quite literally nothing.