When Bioware made the original BG an RTWP title, one of their reasons was that it made for more cinematic and immersive experience. (...) The entire impetus behind Bioware (pre EA) was interactive storytelling. not multiplayer, that came later as internet capabilities improved and coop was gaining popularity.
I skimmed through the articles, and watched the GDC interview (mostly because "making of Baldur's Gate" is actually I would love to learn more about). Maybe it's hidden somewhere deeper into articles but I can't find anything that would support your statement (nor that RTwP was integral to BG experience for Bioware). I would not confuse personal thoughts and impressions (ours or author's of the article), with creators intent or their creative decisions - making a project and looking and final work are quite different things (meaning what benefit you think RTwP brings, might not overlap with reasons it was done that way).
Just to be clear, I am talking about quotes from the devs themselves. I actually didn't find a single thing about them talking about reasons for making the game RTwP (beside adding pause to make it managable). If anything project that later turned into BG, did originate as MMO thing - Bioware seems to have history of grand ideas and scaling down concept (Mass Effect) - but as such from dev point of view BG3 having a strong focus on multiplayer isn't necessary an incorrect take. And while most of Bioware classics were indeed single-player focused storydriven games, BG1&2 did have a multiplayer feature, and project that came after that was... multiplayer, player content driven experiment called Neverwinter Nights. And while Bioware never did a turn-based game - was it really against their core values?
From the GDC talk I took those Bioware ideals: -Always Better - try to make the next project the new best thing you have done -four pillars of bioware (BG specifically): explorations (something interesting on every corner), progression, tactical combat, storytelling.
It's quite possible BG3 might fit all of those. I personally expressed my worries regarding storytelling, as that is where D:OS1&2 were lagging behind IMO, but there is nothing stopping Larian from killing it this time around.
So while it might not be "greater BG" I might have imagined when hearing the name, it doesn't seem to betray Bioware's design philosophy.