Gaming

I skimmed most of this thread and didn't see anyone mention that Steam actually supports third party stores. They let developers sell game keys on other storefronts for free (with limits, granted—the number of keys they can generate depends on sales on Steam, I think.)

Fanatical and Humble only exist because Steam handles all of the games delivery infrastructure for them. That's, like, the opposite of monopolistic behaviour. Name another tech monopoly giving their services away for free so other directly competing businesses can profit.