Playing devil's advocate here. I feel like Play Services is necessary evil. This is the only thing that's keeping the ecosystem from fragmenting further. Look at the OEMs update cycle. If not for Play Services which are updated independently from Android OS itself, app compatability would be a nightmare. There is nothing to replace it with. Nokia tried and failed.
Other thing is, if every OEM starts writing their own API for these services, app developers will have to write apps for each OEM because they for sure will not work with each other. We will go back to the days of Symbian where apps will come with a huge list of phones it is known to work with.
Other thing is, if every OEM starts writing their own API for these services, app developers will have to write apps for each OEM because they for sure will not work with each other. We will go back to the days of Symbian where apps will come with a huge list of phones it is known to work with.