The main reason to stream on any particular platform is discoverability. If you are just looking to stream live video, you can use anything or even do it yourself if you can pay for it. Then just get your audience to go to the right URL.
But if you stream on YouTube, people find you in recommended videos. If you go on Twitch, people click on a particular game and find you playing that game even if they don’t know who you are. People don’t go to Mixer at all because they don’t know it exists.
I wonder if we can make a site that is simply a streamer aggregator that does a better job of discoverability than Twitch, YouTube or anyone else. Then try to get the audience to go through us. Much like Google runs the web, even though other people provide all the content because they control discoverability. If it succeeds, Twitch, YouTube, etc. will become commodities that just provide video streaming infrastructure.