The problem is even if they can build near feature-parity as a streaming platform (compared to Twitch and Youtube), the second they make any discernable profit Twitch is just going to re-assign a few developers and blow them out of the water.
Things like storing VODs (videos of past streams), community tooling, etc., are hard and EXPENSIVE. The developers have a very hard path ahead of them.
Every big company can do this, and it's is precisely why, in a consumer facing startup, tech is often far less important than community building. YouTube or Twitch can build tools to enable streamers, but if your startup is genuinely good to early adopters, and the communities they build, then you can still keep going in the face of an 800lb gorilla.
The tech behind 9 out of 10 tech startups is relatively trivial to clone. The part that's really hard to copy successfully is the people.
It's also worth noting that if you can't do the people bit then even the most brilliant, un-cloneable tech is likely to fail. It's very hard to get customers if people don't like you as a person.