Gruber did point out (correctly, in my view) that the iPhone does attract the more valuable segment of customers, and so they can still do well with a smaller share of the market because they have the customers that matter.
One comparison I found a bit less convincing was when he talked about how iPhone “was never the smartphone market share leader” being behind Symbian and BlackBerry (while still having a superior ecosystem to the companies with larger shares of the pie).
I don’t think that is relevant to Apple’s situation vis-a-vis Android. See, BlackBerry and Symbian were not at all into the whole “ecosystem” thing. Symbian (pre-Qt) and BlackBerry (pre-BB10) developer platforms were technically rough and a headache to develop for. The powers that be behind Symbian and BlackBerry OS weren’t working furiously to match their market size to a developer platform from a technical or business perspective. The difference between Apple building a superior ecosystem with smaller market share then (vs Symbian and BlackBerry OS) and now (vs Android) is that Google has done (and continues to do) spectacular work in recognizing the importance of a developer ecosystem and building the technical and business supports for that ecosystem.
Apple has never been in a situation in which a competitor held considerably larger market share and put just as much effort into its developer platform/ecosystem as Apple did.
Well, that’s not entirely true. Apple did face a competitor like that before. It was called Windows.