The only reason you "don't see a wall" these days is if you are deliberately averting your eyes.... if he'd failed to build it, they'd be harping on it in attack ads, instead, they're complaining about corona if they cite any issue at all, every ad I've heard so far is "Donald Trump is just such a disappointment, vote him out" and it never says WHAT he did wrong, just that, he's orangemanbad.
But it was funny watching them shift from "It's a racist idea, he'd be foolish to propose it" to "He'll never do it" to "he'll never get the funds for it" to "He'll never win the court cases stopping it" to "Dummy Trump thinks a fence is a wall" to "Well, he isn't building enough of it quickly enough to count" to "He built a wall, but he didn't build THE wall, so he lied!" to just ignoring it, to cover up the fact they were wrong about EVERYTHING they said wouldn't happen.