Being from Massachusetts -where the mindset of the typical voter is, "He's a democrat! Just like JFK! That's good enough for me!"- I don't think it's that they DON'T see whats going on,it's that they WON'T see what's going on. There's a hard-headed arrogance to them that won't ever allow them to admit they were wrong. To them,it's more important to save face. They'd rather lose their heads than lose face.
Suggest to a Biden voter that he made a mistake & chances are that he doesn’t want to own up to it. Those who voted for Trump, especially after experiencing his term in office, KNOW that Biden is a mistake, but the Biden voter just doesn’t want to admit making a mistake. Unfortunately the Biden voters carry a lot of weight whether gotten honestly or otherwise.