I'm not really sure what the fuss is about here: yes, if subsequent sales sell tickets for lesser prices, it can be a bit galling if early puchasers bought the ticket earlier at a higher price but there is a reason for this price differential.
First, the person who has bought the ticket earlier has the surety of the good, ie that they've bought a ticket that can be used for a flight of their choice on a date of their choice. Second, the lower latter price is a mere reflection of the fact that the market has not absorbed spare tickets and so QF is selling them at lower prices to attract people -- but this is risky for late buyers as this may not happen and they could have no tickets left (or at a much higher price).
This scenario exactly affected me for travel in a couple of months' time. I bought two Y+ tickets in a sale last year with BA but, low and behold, closer to Christmas I could have got them at even a better price. I was entirely sanguine about that because I had the benefit of certainty having purchased earlier at a good price including that I was able to select from a good range of available accommodation at good prices.