Yes, we've established they are a first party like any other. For the record, if you manage to get Microsoft/Activision, Sony, Nintendo, EA or Ubisoft to publish your game they'll also throw QA, marketing and localization into the mix.

The difference is you'll sign a specific deal and have a publisher at that point. Valve will tell you what they want you to do, then poof out into the distance and give you a link or at best an API to access all of those things at no extra cost to themselves. Their entire business model is for others (both devs and users) to work for them within their systems. Which is fine. I'm also less hostile to the gig economy than many around here, but even I am not gonna actively cheerlead for it.