I’ve questioned this my whole life too. I believe far fewer struggle than what most of them put out. I stutter but I don’t struggle with it as much as I did when I was a child. After therapy and working on it, I don’t struggle with it as much as say, my cousin who isn’t as fluent. I think there are famous people who say things for the dramatic effect to make them seem relatable. It’s a marketing gimmick for them.