I've been a professional macOS developer for almost 20 years now and I can't tell you the number of times that this has been an issue.
With no access (or ability to patch) the platform source code you are left with a) hacky work-arounds, b) re-implement the component or c) change the app's design or feature to compensate. All of which are a pain / more work / risky etc, etc - just to work-around bugs in the platform.
Sure you can file radars (I do), but whether something gets fixed or not, is up to the gods...
With no access (or ability to patch) the platform source code you are left with a) hacky work-arounds, b) re-implement the component or c) change the app's design or feature to compensate. All of which are a pain / more work / risky etc, etc - just to work-around bugs in the platform.
Sure you can file radars (I do), but whether something gets fixed or not, is up to the gods...