Katharine Valentino, one reason could be simply Americans like successes and Joe Biden hasn't provided them in their eyes. Getting the climate / infrastructure bills passed should make a diference. It was always going to be difficult with such slim majorities in Congress.
But Joe Biden is poor communicator of his own plans and achievements. He's a old, not very smart guy with limited vision of the future. The "Built Back Better" slogan says it all with its retro connotation -- it’s Joe Biden.
Nothing much can be done before the mid-terms but a change of leadership is essential for Democrats and the country to move foward.