I do think Qantas has lost it, and my family has been loyal for countless years now. A QF Platinum flying on CX gets much better treatment compared to flying on QF.
Personally, once the Virgin Australia transformation is complete (assuming the product is comparable at least on a price point) it may be good bye to QF, especially as QF is quite useless internationally.
I know this is besides the point of a frequent flyer upgrade. QF service has gone downhill in recent times too. The most recent example, My Dad (Platinum+PG for countless years), on a flight from BKK a couple of weeks ago in J, declined the entree and main meal. He requested a fruit plate with one piece of cheese. This request was denied as it is "Fruit or Cheese only" - with no apology, and the F/A moved on. Not to mention the Boeing 747 featuring lie-flat and not fully-flat seats. I know this may seem like a superficial example, but it is the small differences that can make all the difference in a competitive marketplace.
The point of including the above example - Qantas reduce the benefits to Platinum Frequent Flyers. Qantas charge a higher price for J than any other airline out of Australia yet offer a declining and substandard level of service. Where is the benefit of sticking with QF?