Grading companies don’t authenticate these products as there would be no way to do so with many of the small makers involved, they grade it’s condition. It’s likely this misconception that has them refusing to further grade crypto coins. I doubt it would have been hard to get a fake graded a few years ago. People did used to address this concern with signed chains of ownership and dealing only with trusted members. I always thought at one point reputable sellers with long held collections would be a coveted premium, but we aren’t there yet from my experience.