And this might sound bleak, but i think voters are trusting that biden will be replaced by vice president, if something happens to him, and some hoping that will happen.
This was the case in 2019, at my country, when everyone seemed to think that fresh prime minister of leading party should step aside and he did (not, because of health issues), and was replaced by younger one and in result, we got best prime minister in the history of our country. Sure, she did have haters as well, but that's how politics work.