Because they can, baldy. :-)
I decided to let my hair grow out after having a military cut my entire life. I wanted to see what it looked like.
Fortunately, I am not balding, not even a receding hairline. Except for a little gray in my mustache and around the temples, the hair on my head is thick and blond with a ponytail down my back.
When I'm asked why I let my hair grow out at age 71 years, I respond with, "Because I can!"