They'll never realize they were suckers much less admit it. The older Trumpers were mostly the people swilling Limbaugh and Fox News in the 9/11, Iraq War days. You can hardly find anybody lately that will admit they supported any of that, much less that they were duped by it. Some of the only people I've heard that'll own it are never Trump former Republicans, several of which we have on this board. I've talked with quite a few MAGA in real life who say they loved and still love O'Reilly, Hannity, Limbaugh, and Toby Keith but nah they were always against those wars, even Afghanistan from the very start. When this whole Trumpism thing crashes into the mountain like it did at the end of the 2nd Bush term, they'll quietly change their views retroactively rather than admit they were rubes. Above all else, they'll never admit that the left or Democrats were ever right about any of it.
* The above is the best case scenario, as good as it's ever going to get for the end of Trumpism if we're lucky enough to see it.