My guess it that they’ll do some financial fuckery that shouldn’t be legal, and may not even be, and come away with profit leaving someone holding the bag.
I heard that game has a really bad problem with cheaters. Addressing that seems like it would take precedence over getting the game on Steam. You only get one shot to make a first impression and all.
The game files are already downloaded in the steam version at least. One could, hypothetically, unlock those dlcs even on a normal copy. Steam would have no way too detect that either. Supposedly. In Minecraft.
If you buy it legit on Steam it will force you to install the Rockstar launcher in order to actually play it. It is not known to me if there is a workaround, because of reasons completely unrelated to Captain Jack Sparrow.
Reddit is like, dude you can’t just come out and SAY it.