There's a broader change that is an improvement to the abstraction devs work with, which simplifies coding and results in more GPU acceleration.

Essentially, this article: http://darknoon.com/2011/02/07/mac-ui-in-the-age-of-ios/ will be obsolete.

If it's possible to realise those benefits while retaining subpixel antialiasing, it would entail a complete reimplementation.

On the other side of things -- Light-on-dark subpixel antialiasing has always been a little wonky, and Apple disables it in most dark UIs. Without significant changes, dark mode would've been greyscale either way,