IIRC Larian devs at some point have mentioned that they are fundamentally opposed to the idea of paid DLC now. To the level that a lot of Larian fans would believe the presence of such a thing in BG3 to be a betrayal at first glance, though I also believe in terms of actual practicality that most people will end up justifying it in their minds and come to terms with it within the week.
I think the last game they made that had that was with Divinity 2 (the main series Divinity, not Original Sin), which was well over a decade ago. However, as this is a WotC-contracted game, it's possible that BG3 may end up with paid DLC down the road.
