Market share can be a misleading metric. There may be many more Android phones sold at any given moment, but a majority of them are very low-end phones that have a short life-span. In contrast, most iPhones get used for a long time. If they don't break, they typically get handed down or resold when their owners upgrade. This means that there are (relatively) more old iPhones in use than old Androids, which means that the usage share is closer than the market share would suggest.

Both graphs for iOS and Android are zig-zagging up and down far more than the overall trend. If you're trying to use this data to say Android has no competition from iOS then that's absurd. Their 'share' might have declined a little but during that time their actual installed base ballooned dramatically and is only a little less than half that of Android. Furthermore most of the sales growth for Android is ultra low-end devices that iOS doesn't even pretend to want to compete with.

If one manufacturer keeps selling 85 of every new devices produced and another sells only 15 and this trend continues for 3 years now, I can say assured that one's share is increasing fast, while other's declining. That's statistics and I'm not going down with "iOS vs Android" fanboys fight (I don't belong to either) which one is better. We can only talk about competition in selected few markets (though lucrative ones), but worldwide trend is clear.

>but worldwide trend is clear.

And you're following that trend off a cognitive cliffe.

Apple's market share is in high end devices. Sales for both Apple and every permium Android handset maker have stalled. So the market for premium phones is static and Apple isn't losing any market share in that space. All that's happened is that high end phones have reached saturation point so now it's about market share preservation instead of growth - at the high end.

The only reason the overall market is tilted so highly towards Android is because the ultra low end market is exploding and that's all Android (actually, all AOSP). But that poses no threat to Apple whatsoever. It's completely irrelevant to them. If anything, the growing significance of AOSP is more of a threat to Google and their full-feature licensed Android.

I....don't get your math.

Additionally, Apple mobile devices are typically in use longer than Android (updates available, hardware+screen more robust than the majority of Android devices), so 85/15 sales doesn't translate directly into 85/15 install base.

Very true. My youngest daughter is still using my old iPhone 3GS. Who is still using an Android phone from 2009?

For context, this is what the leading Android handset looked like when the 3GS came out:

https://en.wikipedia.org/wiki/HTC_Dream

I wonder what percent of those 85 are used just a dumbphone.

How do you define a dumb phone?