Okay, semantics; you're right, in my haste I misread the original quote. If you're judging a game strictly on quality, platform has nothing to do with it; most (all?) modern platforms have decent game libraries so dev time just depends on what you're used to. If you're judging a game on mass appeal, popularity, or user friendliness -- or just plain success -- platforms absolutely, beyond a doubt, matter.

As for your last point though... lolwut. iOS was just an example, the same is true for consoles, other app markets, etc. iOS apps bear "no weight" in the statement that a proprietary platform causes slow time to market?! iOS is one of the largest and most developed-for proprietary platforms, which makes it a great example, which means it absolutely does bear weight -- and a lot of weight at that -- in a statement that generalizes proprietary platforms. </semantics>