There are passenger flights from the US to AU (multiple per day but not direct). It's just that USPS won't use them. DHL and FedEx are also still operating between the US and AU (although not direct or cheap).
You talk like there's plenty of space on the limited flights. There is not. Delays in moving their mail into AU and NZ, let alone the other counties they have made this temporary stop to, has been large.
NZ boarders are pretty much closed, so it should be no real surprise it has come to this. You can't expect to carry on as normal with drastically reduced planes landing. I'm helping out with the situation by buying local.
How's is international shipping for you in Cebu?