You'd have to be fantastic at your particular game or whatever they stream on Twitch (I know absolutely nothing about this platform) and great at self promotion. Not unlike wanting to be a rock star or movie star.

I fail to see how it's any more like a lottery win than being in other forms of media, other than it's a very new platform (in the grand scheme of things).

It wouldn't be for me but I'm sure plenty of people are making plenty of money and Twitch has its own Justin Bieber/Miley Cyrus (or whoever is the pop star of choice today. Yeah, I'm getting old).

At least for music, there are some career fallback options if you really want to pursue that path, but lack the charisma / marketing skills to be a pop lead. Orchestras / Broadway, session musicians, game and film composition, studio work (production / engineer / composer), etc. A lot of these paths actually value technical competence way more than the self promotion necessary for pop music stardom. It's an extremely competitive field, of course, but it's possible to do very well as a musician without necessarily being a pop star. I'm not sure if the equivalent exists for Twitch streamers.

It is a lot of networking to help make raids happen early on, a lot of learning to adapt to what the audience wants (which is hard with only a text interface to the audience!), a lot of hard work, and a good amount of natural talent.