Final Fantasy VII Remake has never been locked down as a full PlayStation exclusive. The official wording from both Sony and Square Enix has been that it's "coming first" to PlayStation 4, so it's always been assumed that it'll make its way to other platforms eventually. In other words, it's a timed exclusive.
Anyway, there's been a bit of a development. Based on PS4 box art that publisher Square Enix has added to its press site, Final Fantasy VII Remake will be a 'PlayStation Exclusive' until the 3rd March, 2021. That's exactly one year after the game launches on Sony's current-gen system.
As you can see, a newly designed label at the bottom right of the cover explains all. We wonder whether this will be a label that Sony applies to other timed exclusive titles going forward, or whether it's part of the deal that it has with Square Enix.
In any case, it's quite an interesting detail, although there's no word on which non-PlayStation platforms Final Fantasy VII Remake will come to in 2021. We assume that it'll be PC and Xbox One. Microsoft's next-gen Xbox isn't out of the question either, especially when you consider that Square Enix has said the remake is in development for PS5 as well as PS4.