And that is exactly what rotation will achieve. Legacy cards are expensive exactly because they haven’t been printed in ages. If FFG did not instigate a rotating primary tournament format, it would eventually be impossible to keep everything in print and an MTG-style secondary market would be created for tournament play. This is undesirable. The creation of such a market is inevitable some time way in the future for a potential eternal nonrotating format, but rotation keeps it out from primary tournament play which is a huge driver for prices.
Because it would be impossible to keep all original product in stock. This way, Jackson can rotate out, but if they think the Standard format needs Jackson, they can reprint Jackson (and Jackson alone, not the whole Future Proof pack) in some new data pack, and it’s part of the 5-8 cycles and a limited number of fixed products that are easy to keep in print and for retailers to keep in stock while they are tournament legal. Jackson sees reprint, you can easily use your old copies in your Standard deck.
I am a competitively minded MTG player of 8 years. I understand planned obsolesence and what it does to a customizable card game plenty well, thank you very much.
This. Thisthisthisthisthisthisthisthisthis.
Please, have a look at some MTG cards:


A crappified version of the famously broken Black Lotus, LED was in the junk card binder for TEN YEARS before Infernal Tutor broke it to hell and back. In the process, Infernal Tutor itself basically turned into Demonic Tutor, another famously broken (and banned) card.


Where LED and Infernal were patterned after famous broken cards, Grindstone and Painter are both completely innocuous. Turns out they’re a kill combo together. Took only 11 years for a random, benign printing to break an obscure piece of crap.


Again, two innocuous cards that are pretty much crap alone and were promptly forgotten. Until someone found out that Sword makes Foundry’s effect repeatable and thus a way to gain overwhelming inevitability and board presence really easily. The combo ended up being banned from the Extended format where it was part of the top deck.
This, people, is why rotation exists. Things like these will happen to this game too, it’s inevitable. No one can catch all of these in advance, not when the card can be completely forgotten crap and ten years old crap at that.