It's not odds, it's just that most people have absolutely no idea how to do it. I'm pretty sure I could make it (well now it's way too late), but I don't want to, since I'm not really into video games and the time investment YouTube needs.
Some years ago when I was 13 or so, I had a channel in such a small community you probably don't even know it (german designer community), where I got 500 subscribers in about 4 months with bad to mediocre content. If I had continued that I would probably have about 10.000 subscribers by now, because I would have gotten actually good and you know exponential growth. What I did was (I'm not proud of that), I created fanart for bigger YouTubers and got them to see it, then commented which attracted normal subscribers. Now that was a long time ago, but I know what you would need to apply to video games.
The most important thing is original content. This is also the reasons why, as you said, teenagers fail at becoming famous. Why would I watch your channel if someone does the same thing better or something more interesting? Viewers already have their channels they're used to and to watch that type of content. Your one in a million Minecraft Let's Play #236 is uninteresting unless you have other redeeming qualities (you probably dont). That is what most people fail at and wonder why noone watches their videos. So say you have an original idea or above average great content, good, but that's not all you need.
Think about it, you have just started your new channel or already have been doing it for a few months. How would the average person even be able to discover your channel? You shouldn't advertise yourself in another YouTubers comment section, that's not cool. Rather write a nice comment and subtly mention you do something like them. That's not that effective though. What you should do is get in contact with other YouTubers, preferably over Twitter, say get damn active over there and make friends. They're gonna make videos with you and some of their viewers will become yours and so on. Go on and go on. Now you're at that state where you have about 2-7.000 subscribers and you need a pretty fucking good idea. A german YouTuber who started like everyone else and had about 10.000 subscribers got pretty clever at some point and had a good idea after another. He thought of projects where other YouTubers could participate in, who were even more known than him, giving him more exposure. Needless to say he is, iirc, the third most famous YouTuber in Germany today. You need to come up with that idea that everyone wants to watch.
Other factors are good thumbnails and a view-generating title and of course good quality. Well you also shouldn't come off as a fucking retard nobody likes
To sum up: Orginal ideas, good quality, connections, good first impression and be a decent person (unless that's part of your content)
Edit: Sorry for the long post