Most of the function users care about in their phone, if not implemented by third party, are proprietary apps from google.

Without the app store and the google ecosystem, android experience is poor at best.

The Google ecosystem can drown in bleach for all I care. F-Droid is not bad at all. Downloading apps from the Google store is an awful experience because on that store it's the norm for damn near every application to spy on you to the fullest extent possible. On f-droid, applications the typical application is a good citizen. It's a lower stress experience and a better appstore than either Google or Apple, unless you desire specific closed source software in which case it's no longer an option.

Try this: On Google's Appstore, find a flashlight app that doesn't upload your contacts. Now on F-droid, try to find one that does. This is not an easy challenge!

Or we can also try this: https://www.replicant.us

And what makes Android what it is to most consumers - Google Play Services is also proprietary as well as all of the drivers. Not to mention whatever the OEMs and the carriers add.

Even if you have a completely “open” operating system on your phone, your communications is still going through a carrier that could be “operated by the NSA”.

All of the data collection functionality in Google Apps is closed source too.

Huawei incident has taught that Android is proprietary too. Any country that's at odds with the US will eventually find out that Android will be blocked to their companies too.

The Google Play Store and related APIs are similarly locked down. Not that you couldn't distribute through something like fdroid.

I take your point but android is similar in some respects (Google probably has less interest in your privacy than Apple does).