I know YouTube is a job. People have actually been known to quit their real jobs because of youtube. But its a very low chance of that happening to every YouTuber. Like I said, I know a lot about the program. But those YT who make success like that, have been on YT for years and years building their channel. It didn't come over night. Its very rare when a person is able to make a video one day having 0 subscribers and then the over that week they suddenly have millions of subscribers.
It takes the average infamous person, at least year sometimes even longer to even get 1,000 subs and start getting offers from small companies such as Target and what not. As said before, I know a lot about the program :)
A person like Gabi, who's already "famous" from the Cheer world, it isn't going to take her the average time it would having she been a person like me or you. Regular every day people where it take basically all year to get that to that point. Possibly longer.