GrapheneOS is incredibly focused on security. Privacy is clearly a second thought to them.
GrapheneOS doesn't connect to Google servers by default and avoids integrating any privileged access for either Google apps or partial replacements for those. The main operating systems integrating microG included always granted privileged access for microG, Google Play executables downloaded by microG (droidguard) which run with the privileged access it's granted and other Google apps including Android Auto.
The operating systems you believe are privacy projects greatly reduce both privacy and security compared to AOSP through not keeping up with standard patches, not providing important standard privacy/security protections and adding problematic services.
Lagging behind the already inadequate standard privacy/security updates by months and even years isn't compatible with providing reasonable protection for user privacy. Only a subset of the issues Google classifies as High or Critical severity are backported to the older releases of Android those are usually based on. Taking many months to move to newer releases is much more problematic than it appears. The backports to those older releases also get applied with a substantial delay. Firmware and drivers are usually not kept properly updated even when those are regularly released such as for Pixels. Many standard privacy and security protections are missing or disabled. An assorted of third party services are added too.
Sandboxed Google Play has no privileged permissions, which means that those apps have the same permissions as any other apps you can install on Android, meaning the same restrictions.
All that plus the fact that Sandboxed Google Play is a better approach because it offers better app compatibility and is more secure. microG doesn't meet the project's standards.
Also, GrapheneOS has plenty of users, and we're growing fast. People appreciate quality.
GrapheneOS is not going to compromise on privacy or security, and so far, pixel devices are the only devices meeting the hardware security requirements. People have not had an issue taking that seriously.
That would be an extreme reduction in privacy, not an improvement.
GrapheneOS lets you change aspects of location, including PSDS, SUPL, and network location. GrapheneOS also reroutes googlefusedlocation requests to the OS. If you would rather be able to turn it off entirely, GrapheneOS is is capable of this, not MicroG.
GrapheneOS doesn't have such a narrow focus. As we keep saying, GrapheneOS prioritizes privacy, security, and Android app compatibility. Given those three things:
Privacy: microG's leaks and failure to implement other checks and there's arguably no real gain in privacy since the Sandboxed Google Play approach means Google Play Services and Store don't have privileged permissions.
Security: microG needs privileged permissions to work properly and can also download Google binaries and runs them in that privileged context, depending on settings
App compatibility: It's an incomplete reimplementation. Even microG's GitHub says as much.
Why would GrapheneOS take so many steps back just because the only real compelling argument in favor of microG is "Google bad"?
I am not worried about a random third worlder hacking my phone. This would only be possible if I allow it by user mistake. I am however worried about Google and its business model. As are many others.
MicroG is great because it limits Google's tracking as much as possible. It's lication services can be routed to a more trustworthy party, and you can actually select which APIs microG forwards to Google. Sandboxed Play Services don't allow any of this, and it's bloated and battery hungry in comparison.
Case closed.
Unlike GrapheneOS, CalyxOS comes with a bunch of connections to Google services and privileged integration of those services into the OS. It automatically grants highly privileged access and data to multiple Google apps when installed including Android Auto. It also has a bunch of other problematic third party connections. GrapheneOS avoids bundling third party apps and services not meeting our privacy standards.
microG and sandboxed Google Play don't compare the way you claim when it comes to privacy or battery life at all. GrapheneOS also does replace Google Play APIs including the location API with our location rerouting feature. Unlike the microG implementation, it avoids introducing major privacy issues including microG having a history of leaking location data to apps which aren't granted access to it.
GrapheneOS also doesn't come with sandboxed Google Play included and works very well without it. We implement network location, geocoding and other features without tying those to compatibility with Google APIs. We'll also continue to expand compatibility with apps depending on Google APIs without sandboxed Google Play as part of improving the sandboxed Google Play compatibility layer. It isn't only for running Google apps as regular sandboxed apps. It's also for replacing parts of the Google APIs for apps using the Google Play libraries.
GrapheneOS is more deGoogled than alternatives, so if you're thinking privacy = deGoogling, then GrapheneOS is a good option.
But you seem to be under the impression that microG improves privacy. That's not the case when you look at the big picture. Consider why people need microG in the first place. It's basically there to pretend to be Google Play Services for apps that rely on Google Play Services. Which apps are those? Apps with Google libraries in them.
So, pretend apps with Google libraries are an "app & mini Google Play Services", and the breakdown is like this:
---
App & mini Google Play Services = access is restricted, like other regular apps.
App & mini Google Play Services + Sandboxed Google Play (unprivileged) = virtually the same access as above
App & mini Google Play Services + microG (privileged) = Google has the same access as the situations above, but with worse app compatibility, worse security (especially because of privileged access), and worse privacy (leaks).