Thanks for exactly restating his question. I needed that.

Hey, it made things clearer. For example, when you break it down like that, you might realize that the cost vs. benefit analysis is different for different kinds of software -- there is no "critical level" in general. This is good news for Apple. As their market share grows, software crosses that threshold continuously (as opposed to all at once). That makes their platform become continuously more appealing to users too, creating a positive feedback loop.