After reading the article I realized the way Google builds its own proprietary ecosystem on a top of an Open Source Android OS:
https://loadaverage.org/url/2728528
Some time ago I noticed "decoupling" of Android enhancements from a core Android firmware (in a wider use of "support libraries" than is needed to support outdated Android OS). This article written in 2013, but maybe even more actual today..., opens a wider picture: by decoupling of its own enhancements from Android core, Google "decouples"/frees/takes Android phone users from phone manufacturers.
The only piece, mentioned in the article, which I didn't notice today yet: Google launcher (with its own themes and Android Settings, I guess?!). It would make a Google Experience phone out of _any_ phone that has Google Play Services installed. The Manufacturer's "bloatware" would be hidden and buried

PS: As another article mentioned, 20% of Android phones don't have Google Play Services at all...