I don't see how adding an additional capture framework backend would require meaningful changes to the build system.
With some likelihood, in this case, Apple probably won't have the resources to rework their PR and thus the PR will stay un-merged until somebody of the project has time to merge/reimplement the relevant parts.
Which of course is a total shame and I wonder why Apple didn't have "mergeability" in mind when they decided to create their PR. They must have known that "rework the build system" can't be part of a PR adding a capture backend if they wanted any chance of this being merged.
[0] https://github.com/obsproject/obs-studio/pull/5155/commits
Aren't Apple the richest corporation in the World, how would they not have resources; am I missing a joke? Maybe you meant 'will choose not to'?
Before three was Dallas, there was The Rise And Fall Of Reginald Perrin, in the main arc a dark parody of 70s corporate England. If you could find a better audio-visual exposition of the transatlantic difference at the end of the nineteen seventies, you will struggle to find a funnier one.
http://www.leonardrossiter.com/reginaldperrin/CJisms.html
https://www.google.co.uk/search?q=reggie+perrin+i+didn%27t+g...