Steam however does provide a huge amount of cool features you get for free when you implement their API and use their platform. This effectively creates exclusives because its a pain to implement those things yourself.

That's just offering a good product that people want to use... I find negative views on exclusivity only really come into play when the platform "buys" that exclusivity rather than it being a choice of the creator.

In addition to the other comment: plenty of games are, or at least used to be, available exclusively through steam. Steam doesn't pay for exclusivity, but it still exists

True but that is not a FAULT of steam that is simply the developer / publisher deciding for themselves that is the best place to put it. When I think exclusivity with platforms I only have fault when it's the platform buying that exclusivity ... free choice is free choice.