The problem is that everyone who attempts this tries to start from scratch and then has the network effects problem, when what we really need is for someone to

The problem is that everyone who attempts this tries to start from scratch and then has the network effects problem, when what we really need is for someone to play GNU/Linux to Android's proprietary Unix. Make something that will run the same apps, on the same hardware, but put the user in control of the thing. Then add all the interesting features you wanted to put in your independent system. Which is easier in this case because it's possible to fork Android and start from there. The major problem seems to be the driver issue on mobile. The drivers are blobs tied to a specific kernel, which makes it hard for people to try out the new thing on their existing phone, which suppresses adoption and participation. And that's also the thing that prevents you from even upgrading your old phone to a newer version of vanilla Android. So it seems like what we badly need is a solution for that.