Apple would need to make an ongoing commitment.
Either monetarily, or with personnel. What I would have really liked to see is for them to not only fix issues relating to their own products, but to help Godot as a whole. Maybe, even add Swift as a scripting option without a hard requirement of owning a Mac.
This looks like a one time "gift" of high maintenance code. It's not like when Microsoft assisted with C# support. I don't need to buy a Windows PC or a $3500 Microsoft headset to make use of that.
It's also really rude to just open a giant PR without a discussion first.