We´ve had already several Boxes with ARC-V cards. VRAINS, even. Let´s hope that´s not a sign of Konami thinking the game won´t last long enough before releasing the missing Worlds, and they are putting those cards to milk more money before the end as much as possible.
They are indeed doing it to milk money. But not the way you think.
If they start putting a few Arc-V cards now, when the Ark-V world gets released in 1-2 years you will have to buy 9-12 boxes 3 times to complete your Pendulum meta deck. If you don't buy those boxes from today on you will have to use the credit card.
Start buying the latest box now or you will regret it later.
Instead of releasing and putting all Arc-V cards at the same time in the same box (so that we spend gems only on 1-2 boxes) they keep spreading these cards through different boxes. I don't want to farm 3 times each single 15 boxes that will f*** contain only 4-5 Arc-V cards.
As for releasing Arc-V cards now....it depends on the archetype.
Melodious for example, won't have more than 1 box left, due to small number of cards left. Performapal has ton of cards, however, almost all the ones on this box can be skipped. The full power deck doesn't run these cards.