Well, in 2013 I have the answer to that question from decades past. It wasn't a choice at all. Sadly, now I understand all too well. You see, the hair on top of your head will lightly curl as it thins out. When its compatriots abandon the high ground, the hair that's left decides to fill the space with little twists and ringlets. It dances around in the freedom of all that extra space. I'm roughly the age this actor was then and I know. My hair is doing the same thing.
Yeah, you live long enough and you get your answers ... whether you like them or not.