Apple doesn't focus on market share and it never has. Instead they focus on profit. Take (for example), the personal computer market. According to wikipedia, Mac OS X has around a 7% market share[1] yet Apple's larger competitors like HP and Dell are barely making any money while Apple is still making huge profits. (Not as much as on their iOS businesses of course.)
Apple does focus on marketshare, but a different market than most pundits look at. Even when they launched the iPhone Steve Jobs had a specific marketshare target (I think it was 1% or something).
The issue they have is that they've so dominated the US in marketshare with a great subsidy model that they've generated record profits. It's hard to come down from that to say, "well our profits will drop substantially, but we're happy at being 20% of the US market -- which is actually much better than our wildly successful PC market".
They can't afford to do that -- unless they have some magic up their sleeve.
[1] https://en.wikipedia.org/wiki/Usage_share_of_operating_syste...