Plats and Golds flew more, so were more "īn the know" that at T-80 that these seats were available - so were a large proportion by definition of those that grabbed those seats. Hence I do agree that some high status people will be a little bruised and annoyed by this. But what are they going to do, go to VA, stop flying. So the negative revenue impact will be negligible. Or at least that is how QF would have managed it.
The bigger impact is what if it is successful and people gladly pay for row 4, and your P1s and CLs now loose access to those seats, as they are always bought. That is the risk, QF is now advertising and monetising a benefit that it had not in the past.
If I was a CL or P1 and no longer received regular access to row 4 I would be annoyed...again easily solved but just raising the price until you hit a point that balances demand.