Brexits ultimate failure is already proving to be the fact that it's now "done" and it's getting harder for the loons to pursue it. Even Farage has disowned it.
I think this is a misunderstanding. Last I heard, Farage was still milking Brexit.
He's shifted from
"Brexit will solve all your woes. It's the Elite (who I'm definitely not one of, oh no not at all) who are blocking you from receiving your just entitlement and fulfilling your rightful dreams,"
to
"Brexit has failed to deliver. The Elite deliberately did it wrong to block you from from receiving your just entitlement and fulfilling your rightful dreams."
I think it's important to grasp that this is the modus operandi of Farage, Trump, MAGA, etc.
Nothing is ever their fault. When they make bad things happen to their voters, Farage et al don't experience that as a threat but as a welcome opportunity to blame and stoke up fury against their enemies.
They play everything both ways.