That is the license for the Android Open Source Project. Unfortunately, Google has spent the last fifteen years moving many parts of the stack and almost (if not) all the core apps to Google Proprietary versions. Most apps in AOSP no longer receive updates at all.
The dream is here is not just that we would be running "an open source stack" but that the active development would be on the open source stack. Sure, there are new releases of AOSP. But take a look at the core apps: Contacts, Calendar, Camera, Email, Location services. These are all proprietary now.
Android is open source in the same sort of way that MacOS is open source. There are some open source bits in there.
Who cares about the google user space apps? There are viable open source alternatives for all of them. It's like saying Linux is not open source because Redhat bundles proprietary software with their distro.
This could have been a reasonable analogy if a very significant chunk of applications "for Linux" only worked (or offered its full functionality) if you had Red Hat's proprietary addons installed.
That's just not true. You'll need to give a specific example of which apps are like this on Android. I'm writing this using a LineageOS phone with no proprietary or closed source apps on it right now.
This is true and can be verified by anyone by installing random applications from Google Play Store without having Google Play Services installed. Since relatively recently, you can use some of them via microG, but compatibility varies.
Sure, there's F-Droid and FLOSS software for Android, but if you're already willing to limit yourself to FLOSS Android apps you may very well limit yourself to FLOSS GNU/Linux apps too. When people say "I can't move to Linux phones because I need these Android apps", they usually aren't talking about ones from F-Droid.
You've moved the goalposts. The original claim was that you couldn't run open source android with calendar, email, etc. But that is obviously not true because I'm doing that right now. Now you are pointing at a bunch of closed source software on Google Play, but that's irrelevant to the discussion. And even then you admit it mostly works with the microg compatibility layer. MicroG and WINE are not much different in this respect IMO.
Secondly, you claim limiting yourself to FLOSS android means you might as well just use FLOSS Linux. But that doesn't make sense because the purely open source elements of the android ecosystem work far better than the pure Linux ecosystem, which is my original point. There is no advantage that you can point to for GNU/Linux over Android/Linux other than just being "pure Linux". Android is fully open source and can be easily run unencumbered by proprietary google software. And there is vastly more open source software that is mobile friendly and compatible for Android/Linux than GNU/Linux.
The dream is here is not just that we would be running "an open source stack" but that the active development would be on the open source stack. Sure, there are new releases of AOSP. But take a look at the core apps: Contacts, Calendar, Camera, Email, Location services. These are all proprietary now.
Android is open source in the same sort of way that MacOS is open source. There are some open source bits in there.