Regarding famous personalities who have mentioned that they suffered from stuttering/stammering at one point and overcame it, did they actually have the kind of stutter that troubles one, while growing older?

Regarding famous personalities who have mentioned that they suffered from stuttering/stammering at one point and overcame it, did they actually have the kind of stutter that troubles one, while growing older? Hearing some of their present speeches, it almost feels like they actually never had any kind of impediment. Maybe a little, yes, giving the benefit of doubt, but most of them make it sound like a success story, which I doubt, is of the order that they claim.