Apple doesn’t support it, nor do they care if they break it in the future. Think of it like a workaround that just hasn’t been broken by an update (yet).
This is factually incorrect. They have actively supported this stuff, and most notably, recently released a framework so non-Apple remote storage can reliably integrate into iOS / MacOS without needing to maintain a kernel extension.
Go look at the developer documentation and the WWDC sessions around file management if you don’t believe me.