My startup is under 2 years old, in the same space, and with a much smaller team. We have solved almost all of the technical problems twitch faces, and even released many other features that Twitch is only now also working on.
We have regularly looked at this market and what keeps fueling twitch's success, and strictly speaking people go where the content is. It has NOTHING to do with the user experience of the product, nothing to do with the quality of the tech. If there are 500 people streaming the game you want to watch on twitch and 10 on another platform, the viewers stay on twitch.
Anyway, it is an interesting problem, and one that all competitors in this space are facing. And has clearly not pushed twitch out in any way.
Finally the self promotion if anyone is interested in our product: https://www.stream.me