The problem is aging code sours like milk. I empathize but we need to have people take over these initiatives and refactor them into something easier the maintain. Not saying introduce a new language or anything but change how we fundamentally look at “The Kernel”. I think reducing scope and making it so hardware providers must maintain their drivers is a good start. If your toolchain doesn’t suffice, create a new to…
And then what?
A kernel by itself isn't very useful. Even if your kernel is somehow superior in every way, you need software to target it, so to be a successful replacement for linux you basically have to be completely compatible with any software that currently runs on linux, which not only means a massive amount of work just to keep up with changes in linux, but constraints on your own design.
And then there is hardware support. If you are a fledgling project, how do you get hardware vendors to write drivers for you?