I think you misunderstand me. I'm not saying valves infrastructure isn't valuable, or what they offer to gamers isn't good. Again, Steam is not a product to gamers. It's a marketplace that charges rents to game devs. I'm saying it's not value added to the product that is produced. The product that's produced by the game dev is the same regardless of whether they put it on steam or not.

Most of your points are about how much value Steam offers to gamers in a colloquial sense. Of course, its a lot. But it's not in an economic sense value added to the good produced. Valve taking a 1/3rd cut is more akin to an extractive feudal lord than a collaborator in the making of the good (the game) and sharing in the profits.