Do you know what the rates are, relative to something like bulk mail? I can't think of anything else that has low delivery priority like these packages seem to have. Sometimes even after arriving in the US, the packages take 2-3 more weeks to be delivered though it's usually more like a week. I would say that indicates a lower priority than a comparable package that is sent within the US.

I guess I'm saying that China Post packages are not going from LA to NYC in X days, more like 2X or 3X and sometimes up to 5X. The rates are probably still too low, but I haven't found any authoritative numbers.