That's why I started a Patreon for this, and set a minimum threshold below which the project would not start. I've been there and done "fun challenges only" ports (e.g. PS4 Linux) and I know things never get to the point where they need to be if people are only working on it for fun.

The Patreon turns this into a job, which means I have reason to keep chipping away at all those "minor" things. It also means everyone else working on the project can choose what they work on, and I pick up whatever is left that nobody wants to do.

> If they can reverse engineer a whole undocumented display controller and GPU

Who says they reverse engineered whole of it? Making it display images is easier compared to making it work fast, support video decode, power saving, etc. Nouveau has been around for long time and never transitioned from former to latter state.

> then a fingerprint scanner is easy.

Yes, but it is not the point I was making.

> The barriers to these 'minor' things is motivated people to do it, not anything technical. This is something that can be helped with money.

I've been working on Linux kernel for some time now and I stand by my opinion that the main barrier to do it is technical. You can disagree though.

Apple is probably actively working against you if you want to get the fingerprint scanner and its ‘Secure Enclave’ to work.