Get a cut in the middle of your head and see hard hard it is for hair to grow back over that spot; now imagine your hairline constantly getting scratched, scraped and burned..........Everyone has cuts and scraps around your edge, there is a reason it burns when alcohol is applied post haircut......Doubt me, go wild a month and get a shape up and look how pristine your shyt looks contrary to the norm.............Yea nikkas are talking fully out of their ass in here but it is the Coli so its expected. I've been getting cuts with a lineup weekly since I was 16 and my shyt is still fully intact at age 30, shyt the reason why I need cuts weekly are because of how fast my shyt grows back. And as you said white bols who rock thick hair never get their shyt lined up in the front and I know plenty from my college days who already have their wigs on sunroof status.
Of course there are other factors but over cutting catches up to you over time.................I can't speak for whiteboys and their issues but as a person who cut hair i'm just trying to enlighten you brothers