I would see it as I've had the use of the item for 1 year+ and I paid for that privilege.
i think thats the reason why we get so many temporary items now (teal carnifex, holy weapon, future trinketthing, classchange, spec of light, etc
this way veterans wont be pissed off but the goal your meant is still achieved
sensible marketing
when i read that i though this needs to be done with MUCH care...
otherwise you make your players which have bought it already angry ("why i had to pay x while players now can get it for y?"); the result can be that the big spenders are no longer willing to buy things bcause they learned they will get it cheaper if they just wait a bit
so you reduce your customers to those who cant wait at all while losing the average buyers
especially for really powerful/valuable/rare items
this game is progressive and making these things easy accessible is like making all the effort nearly worthless
(gearreset every year is bad enough!)
as for topic, as Glaida said, P5 is not like you have to buy it for permanenty at once
there is a reason why you can activate it for some hours and do not have to get 10.000/10.000 first
if you have done that often enough, as a reward you get it perm then
there is no hurry at all to get it permanently