Did you read the main points of the press release ? If you (say an OEM like LG) license google play, you cannot create a competing OS based on AOSP. It has nothing to do with OEMs customizing AOSP for the devices they sell. It has everything to do with, say, an OEM selling a different phone that can run Amazon's version of Android with Amazon's services. I think that's one of the reason's why Amazon's phone never caught on. Nobody other than Amazon would be able to make or sell one because everyone had licences from Google.
From the press release:
"Google has prevented manufacturers wishing to pre-install Google apps from selling even a single smart mobile device running on alternative versions of Android that were not approved by Google (so-called "Android forks")."
