> (e.g. GMail, Google Maps, Docs, etc.) as well as the Playstore Framework.
These "apps" are all based around interaction with Google services. Maybe they could release open source versions of those, but then the users would be left with the hassle of having to pay Google for API accesses by the open source code they're running. Most users would simply not bother, and stick to whatever Google is providing for free.
The Google Cloud client libraries are open-source; I don't really see the difference.
I should also point out: often, with this type of project (in-the-open development of a client for a paid service) the client comes with some sort of stub emulator for the service. FOSS developers can test their changes against the emulator, and then submit PRs, which then get run by CI against the real service.
They could offer a digitally signed binary that is free (as in beer ... which would presumably be supported by ads that could not easily be stripped out) and a parallel open-source (ad-free) version that charges users directly for API access (preferably with an "always free" tier of use).
I would pay for that second tier provided they don't mine API usage for data for their search product. I would love to opt out of Google data mining, and I'm happy to pay for the services I use. The closest they have is their G-suite, but I think they still mine data from paying customers.
These "apps" are all based around interaction with Google services. Maybe they could release open source versions of those, but then the users would be left with the hassle of having to pay Google for API accesses by the open source code they're running. Most users would simply not bother, and stick to whatever Google is providing for free.