It's primarily an ego thing.
If Trump wins again now in a rematch and gets a 2nd non-consecutive term while their guy dies forever remembered as a 1 term loser (Let's be real: Biden's body, mind or both ain't making it to 2028), that's arguably more humiliating than if Trump had just won 2 times in a row, and they know it.
I think "smarter" is the wrong word to use here. Libs use that like an inherent trait, their "team" has the trait of "smart" and the "bad guy team" therefore does not. They need to feel smarter than others, as a way to reinforce their worldview without actual evidence. So when we show knowledge that they lack it feels like a personal attack against them (which is why they freak out when we share a source that contradicts their nonsense.)
They want to be the "smartest person in the room" at all times, not realising that if you're the smartest person in the room, you're in the wrong room.