Hi, I think that early access games can have a 'early-access' label on them. Maybe itch.io can also add a category for those games only in early-access. :)
I agree with you for the simple fact that when you purchase a game and you see that it was made like two or three or a year ago you think that it would be finished by now or at least out of level of Polish that would be visually presentable or the gameplay would be good enough or fluid. But that's not the case so An Early Access label or not finished yet or incomplete label would be great.