AOSP does not include proprietary apps like the Play Store, etc.

In order for device manufacturers to get the Play Store on their phone, they have to give in to Google's demands to add the Google search box on the home screen of the phones.

Apart from this, Qualcomm doesn't release open source drivers for GPUs etc, making it even harder to use pure AOSP on flagship devices.

Qualcomm blocked Google from using Proprietary Android on its devices! One of the Nexus phones couldn't upgrade the OS to the next version due to Qualcomm drivers.

> In order for device manufacturers to get the Play Store on their phone, they have to give in to Google's demands to add the Google search box on the home screen of the phones.

What's wrong with this? The Play Store is subsidized by search revenue, it makes sense to tie them together.