You are right, nothing is impossible, but amount of work to create something on a level of of BG3 is unlikely considering it took Larian 3 games to get there.
You're implying that Larian have actually been evolving with each game. Which is not necessarily the case (Especially since most of the improvements from DoS2 to BG3 are simply just using the DnD ruleset instead of Larian's own thing).
You're also implying that a "BG-esk" game requires Larian's level of competence. Which is not the case (And is arguably not a particularly high competence when you account for the whole "Act 3 sucks" thing that is prevalent in Larian titles)
BG3 is not some unreachable level of video game expertise. It's simply the first AAA CRPG, that happens to also be using a very big IP.
BG3 is also not some uniquely "BG-esk" game that no-other game or company can ever approach. The fact that it gets compared to the ORIGINAL games for it's "BG-ness" is literal proof that Larian has no monopoly on something being "BG-ish".
The thing I brought up with Elden Ring, is that FromSoft shortened development time by reusing assets. It's not that they had especially good experience in creating an open world game (They actually had very little) they just had a lot of time saving from copy/pasting existing assets into the game. Meaning, that it's not that other studios cannot create an open world. It's just it'll take longer to create assets for it.
