There are choices out there. Whoever says there's only android and ios is, to put it frankly, wrong. However, they're entirely right that if you want the richest and most varied offering of applications then yes, those are the two you should go for. Absolutely.
I've recently taken the choice to leave the android sphere, I'm still going to keep a 7" android tablet around for games but my current phone (Note 2) will be my last android phone. When mates heard my rumbling about leaving the os the very first thing they asked was: "Is it because of the fragmentation?"
No, it isn't. Fragmentation of the android platform has become an empty, misleading buzz-term. It has never represented a problem for me neither as a developer or user. I'm leaving for a reason that is causally related to brand loyalty: it doesn't appeal to me any more.
Android/Samsung/Google, in no particular order, subjected me and my better half to: Knox root-witch-hunt, abandoned devices without security upgrades, the terribad filesystem on the original galaxy s, MANDATORY HDCP on hdmi-out at all times even when viewing our own photos, google being shown as leaking data to anyone who wants it, locked bootloaders, bloatware, proprietary restore systems when their own OTA upgrades fail and, finally, an interface that I just don't find intuitive.
I had brand loyalty to both android/google and samsung. When it was time to pick a new phone it wasn't a matter of picking the os or the brand, it was just a matter of figuring out which of the new samsung phones I wanted. Once you remove the brand loyalty I'm left with an os that tries its very hardest to disassociate itself from all the aspects of linux that I find the most valuable and versatile. And a manufacturer that does everything it can to reduce the amount of choice you have when using a product that is based on the most open of choices. I'm done.
So, what am I switching to? I'm interested in both the Jolla and Ubuntu phones, right now it could go either way and will depend a lot on the hardware. Project Ara fundamentally solves the hardware conundrum, assuming I can run something other than android on it.
How do I harmonize my previous statement about apps with the consideration of using the newest phone os'es? Because they run applications I've used since before either android, ios and windows mobile even existed. The killer apps for them don't need to be written, because they already have been.