> It's still more open than AOSP

I don't think this is true at all? AOSP is completely open source modulo driver blobs (which Sailfish has too) and Google services.

One can make a fully functional system, modulo drivers, out of only open-source components using AOSP. It's not possible to do this using Sailfish; the compositor, UI libraries (Silica), and most of the "core" apps are still closed source.