R.P. in Northfield, IL, asks: OK. Why the heck is Joe Biden's approval rating so low? By many measures, he's really accomplishing some good things—unemployment is decreasing, the economy is faring quite well, inflation is falling. Foreign affairs is a strength of his, and he's demonstrating that he's using that skill to accomplish a lot. Domestically speaking, that new commercial he made using Marjorie Taylor Greene's own words to tout his accomplishments says it all. It's a laundry list of his successes. I know there are always going to be haters, but the low rating must mean that even a fair number of Democrats don't approve of the job he's doing. So again, what the heck?
(V) & (Z) answer: We think about this all the time, and don't have a great answer for you. The odds are pretty good there won't be a good answer until a fair bit of time has passed and scholars can look at the big picture.
What is clear is that voters on both sides of the aisle have gotten more parsimonious with their approval. It used to be customary that, on the whole, more Americans approved of the president than disapproved. For example, Dwight D. Eisenhower's average Gallup approval was 65%, John F. Kennedy's was 70.1%, and Lyndon Johnson's, even with the Vietnam War, was 55.1%. Since LBJ, however, only three presidents have finished with an average above 50%: Ronald Reagan (52.8%), George H.W. Bush (60.9%) and Bill Clinton (55.1%). If you toss out Bush as a fluke powered by his sky-high Gulf War numbers, it's really just two of the presidents in the last half-century, and Biden is not likely to buck the trend.
It is certainly the case that presidents can no longer count on their own party to be squarely behind them; there are always some Democrats these days who think a Democratic president is too lefty/not lefty enough, and always some Republicans these days who think a Republican president is too righty/not righty enough. However, what appears to be the most significant dynamic is the almost total lack of aisle-crossing. There is virtually nothing a Republican president can do these days to win the approval of Democratic voters, and virtually nothing a Democratic president can do these days to win the approval of Republican voters. That is probably a product of the partisan media, at least in part, but may also be due to other, somewhat hard to identify, factors.