Steam didn’t get to where it is because of market abuse but because of providing a good service, or at least a service that was better than anything else at the time by far. Valve are reaping the rewards now, but are also still providing an arguably better service than it’s competitors. It’s a bit odd that you want to punish a company just for being successful.
Valve isn’t perfect and they’re profit driven, but they’re privately owned and the goals isn’t maximizing profit, which isn’t something you can say about most of their competitors.