A better comparison is the (derelict) Mac App Store. Apple still continues to charge their 30%, and their most professional developers and customers continue to avoid their store. Adobe doesn't sell full-fat Photoshop through Apple's storefront, Avid doesn't bother with it for Pro Tools, Ableton, Bitwig, Sony, U-HE, Sonar, Spectrasonics, and even Panic don't fully commit to Apple's offerings. Nevermind the fact that ubiquitous components of modern professional software development (git, bash, grep, make, the lot) isn't even allowed to be distributed under their own terms on the App Store. If nothing changes, Apple will become Lord of the Flies.

If Apple wants to be Steam, let them play Steam's game and see how far their philosophy takes them.