Unchecked Apple without real competition would be worse than the status quo.
The point, perhaps, is for one to emerge as the prominent choice, the correct one. Diversity however has its own value.
https://source.android.com/docs/setup/contribute/submit-patc...
If you develop for a diverse set of user you need a lot of effort.
The Play Store is mostly absent from China, and I really don't know how that ecosystem works.
Was there one ecosystem?
I would happily leave Android and go with such a fork. Instead, each (Samsung, Huawei, ...) try to make their own thing. And good luck to them to beat Android on their own.