Their strategy is growing markets, especially in india, and africa, and of course China. It's where the chinese oem dominate. Beside chinese OEM, i think the only other player is Samsung. So google strategy seems to be to circumvent people from misusing their OS by blocking certain services (mainly ads). This is done via apps from fdroid, and rooting and what not. If google can control how people uses their devices (block vpn based adblocking, or rooting all together), they have better grip on the market. At the end of the day, Android is front for an ad platform.