Earlier quoted context omitted.
Almost all of it is closed. Since the G1, the following parts are just some of the many that were removed from the open project and replaced with proprietary ones: Launcher, Dialer (the actual phone app), Contacts, Calendar, Email, on-device Search (last open in 2.3.7), and many more. Everything that the user touches or sees is closed source.
All of those apps exist in AOSP and have many open source equivalents not developed by Google. The platform that those apps run on is just as open now as it was in the G1 days.
The versions in AOSP are heavily cut down on functionality and barely even work.
Im the days of the G1, the actual Google Talk and Google Search apps were open, the Google Books app was open too!
That was the Android we bought into: one where a default install was entirely open, and living without any closed source apps was easily possible.
Today, that's long gone. Play Services here, SafetyNet there, Google®™© apps in the middle.