If they aren’t disproven in court, then it’s easier to continue the lie. I think they might have learned their lesson from Mueller, who shut down Russian Collusion (for the most part) after two years. Without Mueller, Russian Collusion could have remained an open question indefinitely. I think this is also why they won’t bring charges against the people being held indefinitely for January 6th. If they have to charge them with mischief instead of insurrection, then there was no insurrection.