Can you point me a reference to a single phone? A phone running AOSP with open-source kernel drivers and not a single Google closed-source binary. Good luck to find that.
The only project I know about doing that is Replicant and targets ancient phones. It's also a community run project, none of those phone came fully open from the factory either.
There's not a single phone on earth running AOSP, you can't really compare it to Ubuntu. It's not made for tinkering or user ownership.