I don't think that taking a cut for the sheer exposure of the platform is the same as exploitation. Even small devs make more money by an order of magnitude through steam than they would if they did not.

Steam costs money to operate. I really don't understand why people think steam should just be valorous and noble and not make any money. Labeling them the middleman implies they don't do anything. They provide a service in the same way a grocery store is there to make sure you don't have to drive to a different farm every time you want a different kind of vegetable.

That's really the only problem I have with what you said. Of course people shouldn't be loyal to companies, I'm just pointing out the flaw in your logic that people should be loyal to people instead. Any type of figure that you don't personally know is primarily a concept.

But also, "Behaving like a responsible consumer" is an idealistic fantasy that mostly fails because of the prisoner dilemma. If not enough people do it, the only people who suffer are the ones doing it. That base mindset might be overcame on an individual basis, but it's rarely popular enough to gain the traction required for actual change, and it becomes more and more difficult the more people are content with the service.

It doesn't help that steam is essentially the only game launcher that isn't tiny or garbage.