The level of entitlement people in this thread are exhibiting over their consumer entertainment products is pretty baffling. Don't like Steam? Don't use it. Don't like the cut you get on workshop goods? Don't make them. Valve created a digital marketplace that provides a tremendous amount of value to a lot of people, and has made a lot of people a lot of money. The idea that they have an obligation to give a certain amount of that money to e.g. people who make workshop hats is absurd
unless at some point ever Valve made some concrete commitment to pay them a certain amount.
Honestly at what point in the history of mankind has anyone even contemplated making a living wage off of selling hats you wear in a videogame? The fact that this is conceivable is due to the system Valve built. And yeah, that means they get to profit from it,
so long as they are not engaging in any coercive behavior. And no, no one is being "coerced" into buying a videogame. Housing, food, healthcare, transportation? Sure, let's talk about the necessary rules and regulations we need to ensure that as many people as possible have access to those basic necessities. Access to videogames, and revenue from creating content for a videogame you don't own, is not a basic necessity.
"Sure, I won't charge a commission, as long as you give me free advertising." There's nothing wrong with the practice in particular, but Valve isn't doing it out of the goodness of their heart.
Valve does not have a heart or intentions. The people who work at Valve probably have a wide range of attitudes from idealistic to mercenary. But why does any of this matter at all?