There's a "collaborative project to unify the Hardware Abstraction Layer for projects which run GNU/Linux on mobile devices with pre-installed Android" called Halium.
Complete with the device mfg's unpatched 3.10 kernel.
Thanks, but no thanks.
I wouldn't write it off so easily, it makes sense as an open source alternative to google's project treble albeit with parts of android still running underneath. A stable linux HAL on a few widely used devices would make all the upstream dev easier. Even if you are stuck on an older kernel because of a blob driver, it's progress and similar to when you can't upgrade the kernel on your laptop now because nvidia haven't updated their drivers.