It is misleading. It is 30% of the entire revenue of the game. And it is objective whether Valve deserves 30% of that revenue. It’s also true that games aren’t locked to the Steam platform and can absolutely make money outside of Valve’s influence. History has shown though that it is less profitable then being inside the Steam ecosystem.
You know books haven’t been innovating graphics for centuries. It’s scary how many people have been using old books for recreational use. How can newer book publishers compete?