Unfortunately with YouTube's growing popularity, getting famous like
@AlexGotBeats said, you usually have to be good looking, talented (personable on camera, entertaining if you're a gamer, that kinda stuff), and have money to invest into advertisements to put your channel name out there. It's sad, but with how this world works, you have to be superficial sometimes.
Either that, or you get someone huge to shout you out and blow up your channel. But even then, those subscribers usually only subscribe because their idol told them to, so 50% won't even watch your videos.
You gotta invest some money out of your own pocket now a days to get anywhere, but that's just all part of the climb.
Because even if you invest money, you gotta be entertaining. If you're not entertaining, you're wasting your money.