iOS is a luxury brand (remember that carrier subsidies are smaller in the EU and are not allowed in some member states). So, realistically for a lot of people there is only one kind of affordable smartphone and that is an Android phone.

As you mention, AOSP alone does not give you much Android and Google is likely to dictate all kinds of terms to use the Play services, Play Store, etc. So, the question is indeed does AOSP give enough to argue that Google does not fully control the Android market.

Personally, I am not sure this is the most problematic aspect of Android though. If we assume for a moment that Android is a near-monopoly in the EU, the more troubling aspect is that people can only choose between having no smartphone (which is becoming harder) or letting Google suck all kinds of data out of them. In other words, only when you are rich enough, you can afford not to let a company suck up a lot of your private data.