There’s literally nothing we’re told about clones that preclude them from still being around or even just a possibility.
Other than that they were once common enough to fight a war over, and nowhere to be found today. Agreed that there’s a chance they may have all collectively decided to do a post-war retreat to Ceti Alpha V and not sign the required release forms allowing them to appear in any films. Same probability as there might really have been a Battle of Wigglypants, or that Vader has a third arm you never see because it’s under his cape. Not mathematically impossible.