That is the thing, most of the people that are "famous" on YouTube didn't try to be famous at all. They just posted videos they wanted to make and created a following. But one thing is for certain. If you don't get that following early on it is unlikely that you will gain it later. I take myself as an example, 3 years, 2.7K subscribers. Not a success story at all. But I don't care too much about the numbers as it is the fun I am having that counts. Being able to reply to nearly everyone that comments on my videos is pretty darn awesome.
You either got that personality that draws people in or you don't. And that is completely fine, if you can live with being at the bottom of the food chain that is. Although, if I am completely honest, my 2.7K subscribers might seem insurmountable by those that are just starting out too. I follow a channel that was below my subscriber count a week ago and now blasted past 4K subscribers today. It didn't phase me at all. They got the goods, I don't. And I knew that from the first few months in that I didn't have it. I told them they would hit 10K subscribers in no time. And I am going to be right. A month from now I reckon!
I just do it for fun. Could I do it for a job? Absolutely... if I could review cars from car enthusiasts for the rest of my life, build a classic car as my channel mascot and interact with everything and everyone car related and get paid for it? Oh heck yes. So much yes. But, it's not in the cards, and will likely never be. It's good to dream, but don't make those dreams drag you down. Reality sucks, but you better embrace it early on.