Shorter version: it's bullsh*t.
Longer version:
(1) it is inaccessible to almost everyone.
(2) anyone who could achieve it, could afford to continue flying in F or J and maintain WP or probably P1 indefinitely anyway.
(3) it therefore offers little - if any - incentive to anyone.
(4) those who need it have no hope, those who have hope have no need.
(5) it is unquestionably unfair, when LTG is 20 x annual gold but LTP is amost 54 x annual WP.
(6) QF knows this hence the "bankable" years of WP as a milksop to appease us.
(7) yes it has some extra perks, but why? it would be better to offer a genuine LTP at around 28,000 SCs and a genuine LTP1 at 75,000
(8) after all, 75,000 is just over 20 x annual P1, so it is the appropriate threshold for LTP1.
(9) yes QF is a business and it can make the rules, but the whole point of a loyalty program is, well, loyalty. So if your program seems horribly unfair, and the benefits seem elusive, if it generates as much angst as this issue generates, then it's not doing its job.
(10) QF is already risking this because the Classic Rewards everyone chases - premium cabins on international long haul - have become so difficult to find, and almost impossible on QF metal. Maybe availability from SYD is better but from PER it is abysmal.