An order of magnitude doesn't mean anything when the market is much more than an order of magnitude larger.

It does, because who are you selling to if 90% of your audience never heard of the original thing?

If you don't know for an absolute fact that the primary reason that BG3 pushed Larian past niche into a blockbuster success is the IP, you don't know what you're talking about.

You don't see anything wrong with you asserting the opposite? It's not even sort of ambiguous? Yes it is! lol. The only way to prove otherwise would be to time travel back to 2017 and revoke the IP from Larian. D:OS2 already sold significantly more than its predecessor, and word of mouth was almost surely going to make their next game sell more than that too, and it turns out things like performance capture help to really pull people into a story-driven game. Most people who picked this game up probably couldn't even tell you that Baldur's Gate was a city and only knew that it had two previous iterations because this one has the number 3 in the title.