What the commenter above was referring to is special API access for Nokia and a few key third-parties that regular devs were not allowed to use.
It was a strange time for Windows phone. Agreed, such a shame, it was an interesting UX-first design for its time.
Doesn’t FDroid still not allow automatic updates due to restrictions in Android?
Meanwhile yes the Samsung galaxy store has extra power over other store alternatives because they are a powerful OEM and can modify Android as they like.
Other OEMs (ones that are often not able to use Play Services) also have their own 1st party app store. Amazon is one, but many others exist in China.