But to really compete with Twitch, which has reported that it has 140 million monthly users, Microsoft needs to do more than spend a few million dollars on a star streamer, said Doron Nir, the chief executive of StreamElements.

“When it comes to having a streaming platform, this is a billion-dollar game,” he said. “It’s going to take a lot more from Mixer to really take away from the enormous audience that Twitch has.”

Mr. Nir said he didn’t believe the deal for Mr. Blevins was bad for Mixer. It still brought the platform widespread media attention and put it in the conversation. And Microsoft was not discouraged, bringing over Michael Grzesiek, a professional gamer known as Shroud, and Cory Michael, a streamer who goes by King Gothalion, from Twitch.

Given how enormous the Twitch community is, it’s hard for content creators to justify streaming on smaller platforms. But some streamers are drawn to the opportunity to start fresh.

Chris Covent had long dreamed of becoming a full-time video game streamer, the modern version of public-access television personalities who broadcast their lives on the internet.

But after four years on Twitch, Mr. Covent was not gaining the following that would allow him to leave his job as a Boost Mobile store manager in Flint, Mich. He decided in 2016 to make the jump to Mixer.