It is far too early to say anything for sure. Steam Broadcast could end up vying with Twitch and Azubu for the attention of viewers or playing the role of a supplementary streaming platform.
Half-Life and Portal writer Erik Wolpaw has detailed how his team has been using Generative AI for research and development at Valve.
Valve has responded to New York Attorney General Letitia James' lawsuit against the firm, stating it does not believe that lootboxes in its Counter-Strike 2, Dota 2, and Team Fortress 2 games unlawfully encourage minors to gamble, adding it was "disappointed" to see the action go ahead despite efforts to "educate" the NYAG about virtual items since "early 2023."
As said in article, too early to say but i would hope that Stem doesn't lock down its games to be streamed on broadcast only as that might hurt them more than helping.
Maybe not as a direct competitor, just as an alternative