So at the moment Apple hold the 1st place in mobile OS marketshare, I feel the unfortunate thing that will happen as marketshare drops Google will slowly move to supporting projects other than android, and eventually drop support entirely and focus on making better iOS apps, Device makers will start making their own operating systems with tighter locked down appstores in order compete with iOS, we already see this with Amazon planning to switch to a linux based OS in future fire devices.
Also Android has strategic importance to Google. Their philosophy is to spread out and control their own platforms.
Normally Google, since they offer a search engine, ad platform and online services, could have stuck to just renting servers and cloud.
But they didn’t, they also created their own massive online storage platform, their own cloud platform, their own browser and browser engine, their own mobile platform, their own PC-based platform, their own wearable platform and so on.
They will never give up Android, unless perhaps they will have something else already prepared to replace it. But it would be an insane undertaking to move everything over, but to mention having to drag consumers and manufacturers and app creators kicking and screaming every step of the way.