I have mixed feelings on it.

When I was putting out games, publishing on Steam would mean a guaranteed 1 million impressions on the "New releases" list. That's incredible exposure for an indie title, which often succeed or fail on exposure alone.

But 30% can be a lot for those same indie teams, especially combined with taxes. You can put years of work into a title and lose half the money it earns to groups that didn't directly contribute at all. It can easily be enough money that long-term support or follow up games just aren't viable. It can be your entire outsourcing budget or a whole employee for a year.

And after that initial exposure, you're not getting much for your perputual 30%. The value of Steamworks can vary greatly game by game so you could end up paying $30k for $100 of bandwidth and minor marketing through things like sales and rich presence.

I would much prefer to see something like "30% after the first $X in sales". Their cut would kick in only after they've demonstrated their value as a platform and small teams wouldn't have to watch a company with billions of dollars take a very large bite out of their very small pie.