It's been clearly hinted that you need to make some real impactful choices by the end of chapter 1 in regards to followers.
We just haven't seen it yet
Supposedly it will be the same as DOS2 where the ones not in your active party will be eliminated, which I HATE. I'm fine with them dying based on our decisions, but a blanket wipe of those that we don't at that moment have active is definitely not fitting for BG3 or even an RPG based around a party.