I think, to some extent people are getting to hung up on this. When a DM creates a Forgotten Realms campaign, because he does not follow the exact formula Ed Greenwood uses, does that mean it is not a Forgotten Realms campaign? If a DM uses the Underdark source material for the basis of his campaign but does not directly follow it, does that mean the campaign is really not in the Underdark?
BG3 is a new DM with a new version of DnD. While it does not feel like the original games, these two factors can actual explain that.
