Is Australia Post really listening to it's customers ?

Why does the prices jump from 500 grams to 3 kilograms and why  don't they have a one and two kilogram price ?

Australia Post prices is starting to become  one of the most expensive in the world for postage and it looks like they would rather deliver parcels from overseas at loss than deliver parcels from Australia at a profit .

I know many booksellers who have stopped listing many of their books over 500 grams because the price of  the postage has gone up almost 50% percent in the last few years .and it is almost impossible to compete with overseas sellers who are only charging their buyers around $4 when  Australia Post charges them around 3 times the price to post the item in Australia to an Australian address