They are dependent on the AOSP releases (which Google develops) and on the manufacturer updates (and because GrapheneOS runs on Pixels, then it goes back to Google again).
I can understand relying on an OEM to provide hardware support for a given model - but I'm finding it hard to understand why they're unable to continue supporting a release just because the upstream removes support for something.
I'm not even really sure what you mean by "manufacturer updates".
The more I hear about this project, the less is sounds like an alternative OS and more it sounds like a thin skin around whatever shit Google throws out, to be honest.
I can understand relying on an OEM to provide hardware support for a given model - but I'm finding it hard to understand why they're unable to continue supporting a release just because the upstream removes support for something.
I'm not even really sure what you mean by "manufacturer updates".
The more I hear about this project, the less is sounds like an alternative OS and more it sounds like a thin skin around whatever shit Google throws out, to be honest.