The dev made money from at least the iOS, Android and Steam Greenlight versions. They also offered it for free.

https://www.giantbomb.com/articles/mcpixel-embraced-piracy-lived-to-tell-the-tale/1100-4366/

Curation and encouraging PC ports when the store was relatively new != exclusives.

Not really, they’re the villain for doing exclusives. Steam never did exclusives, at least not with 3rd party devs.

Steam reduced their cut to 20% for the biggest publishers, let’s see any of the others do that. They also allow other stores on the steam deck. They also allow steam keys and shouldn’t demand MFN pricing.

Their cut is worth it to users for the same reasons as an iOS and Android user might say, except when it comes to switching platforms, your steam games can come with you to rival platforms and not just friendly ones.