This ship has sailed, in the past Amazon's store did not succeed a lot, but there are already a few important enough offsprings: * Huawei with separate store and no Gapps * Samsung with importantly different browser and ton of extra features, also another store * in China the app-in-wechat and similar are a major thing

If you develop for a diverse set of user you need a lot of effort.

Apps that run on the Kindle Fire can't use Google Mobile Services, and the Amazon appstore is missing many well-known titles.

The Play Store is mostly absent from China, and I really don't know how that ecosystem works.

Was there one ecosystem?

There already are multiple different android ecosystems today. For example Samsung has SDKs that have features when targeting their flavor of Android. There will still be a common base.

> Developers aren't going to develop for five slightly-different ecosystems

The point, perhaps, is for one to emerge as the prominent choice, the correct one. Diversity however has its own value.