He has done it to himself. In June of 2020, he didn't say the science changed when asked specifically about why we were not wearing masks from the beginning. Saying the science evolved and we learned more would have made sense and would be consistent with his previous statement. It would have also aligned with what the surgeon general was saying at beginning. But rather than doing that, he talked about health care workers and the risk to our mask supply. Except he made no mention of that in March when he told us masks were not necessary. Hence the problem that he, and maybe those around him as well, created.
And then we can look to herd immunity... While he did say this goes up/down based on new studies, he also came out with this beauty of a statement....
"When polls said only about half of all Americans would take a vaccine, I was saying herd immunity would take 70 to 75 percent. Then, when newer surveys said 60 percent or more would take it, I thought, “I can nudge this up a bit,” so I went to 80, 85." Like what the heck?!?
Bottom line, how he is perceived is of his own doing. "The science has evolved" doesn't provide him cover for his statements. While I have never thought Fauci was doing things out of malice, I always thought he was the wrong face that our leaders were putting on TV as a messenger to the American people. He is just not that good at it.